302 Had that DZ code in 1969. In 1967 it was a small journal MO or MP code. In 1968 it was a large journal MO code. So keep your eyes open for the codes also. Great video.
A 1969 Z28 302, with a set of headers probably made over 400 HP ; but the sound of that little motor winding out to 7,500 RPM was pure music, that was guaranteed to put a huge smile on your face !!! 😮😊😊
@@welshrarebit9238 I am going to say that would be some impressive feat considering racing engines such Nextel Cup, F1, Indy, and even sport bikes have piston speeds that are not exceeding 4800 feet per minute and in the extreme upper end exceeding 5000 feet per second. A Chevy 302 has a 3.0 inch stroke and to turn 10,000 RPM it would have to have the piston traveling at 5000 FPS. The maximum safe piston speed is 4500 (with fully forged and balanced rotating assembly using aluminum rods). This engine would also need to have the valve train components to match this RPM. It is possible, but very unlikely.
@LionWithTheLamb I knew a man by the name of Tom Knolf who raced a '69 Z-28 in the nhra. He dumped the clutch on the car at 10,000 rpm and shifted at 9500 rpm. I've heard many of these stories.
1967 blocks (3892657) were MO or MP coded and small journal. 1968 blocks (3914678) were MO but large journal. Only the 1969s were DZ (3956618 or 3970010). Most of the early cars had the 618s and 0010s were mixed in later in the model run.
I seen two DZ marking 68&69 if I’m not mistaken 68 add some small and big journals I’m guessing it was ever left in the dealer that they didn’t sell but large journals for 69👍 but mo & mp are Real 302 sbc some people think if it doesn’t say DZ it’s not real
@@chicanou-turn5056 By the numbers in 67 the 302 was a small journal block (327 block number) and there were about 6 numbers in 67 for a real 302. That was cut back in 68 to 4 small journal 327 block numbers. As far I I know, all the 69 DZ 302s were large journal cranks with a totally different crank then the 67 or 68. Am I wrong in that thinking?
@@hydroy1 you are right majority of the 68 and 69 dz Motors are large journals because it was a 350 / 327 / 302 but there was also small journals that they were making in the factory make 1967 going onto 1968 that were small journals and this is 327 /350/302 probably like the last run of the small journal they got tossed into 1968 and then after that everything went large journal I read about it somewhere also 1967 and I want to say 1968 I might be wrong but there was a 302 mo & mp They were real 302 engine before they put the DZ stamp on it in 1968 at 1969 so early 1967 engines did not have a DZ stamp on them👍 But we’re still real DZ 302 motors
Got a 68 block only, looks as if top of cylinders are slightly chamfered near top. It has been decked and code is not visible anymore. Anybody got any info on this setup?
A good friend of mine's Dad was into Drag racing back when i was in School back in the 1960's. They were racing a 1940 Willies the engine was a 283 Bores out to 302 way back in 1963! Dragracers used the 302 long before Chevy made the Z/28.
I built one back in the '70s. Started with a '60 Corvette base 283 engine that had a cracked block, used the a block from a '65 327 Chevelle and a set of flat top pistons and the rest was from the 283 except the intake which was an Edelbrock Torker topped with a Holley 600 double pumper. Put it in a '71 Nova and that thing would flat out run until I let a buddy borrow the car while I was working one night and he blew the engine up trying to street race it.
Bummer! I took a 265 & bored it out to a stock 283 ,powerpack heads ,11to1 pop ups ,400 camshaft,c3bx intake & 650 doublepumper,double pumper,, LOVE SMALLBLOCKS
Thats what I been holding back my LAST NOS 283 steel crank for. But today it's hard to find a standard bore 327 block that doesn't have issues. They all need to be sleeved as most are already +.060 over and need boring. 8 sleeves installed are very pricey when you add aline bore, decking, open up the clearances and everything else needed. I just did a stock rebuild on a 67/ 327 for my daily driver and I dumped $6,500.00 in that puppy real quick for a STOCK rebuild as I don't miss a thing on machine work.
@@hydroy1 I've got a 327 actually I've got at least four of them. You might call me the old bones collector when it comes to 327. This 1327 I first start out with talking about. 1965 Chevy Impala that my uncle bought new and he parked out in the late seventies out at the farm. It was a station wagon he's special order. He wanted hurry up and get those groceries. I don't think it has more than eighty thousand original miles. He just got tired of the old car and park it out at our farm. Said here it is. I used the top end of the engine including four-barrel intake on no 327 that I built and this is all back in the 80s. I still got that wagon with everything but the upper end and front seat. well anyway you're right they're usually worn out three times over. I once drove five or six hours each way just to pick up a 327 that was built by an aircraft mechanic/Machinist. He had passed away and the engine has a few miles on it. I'll have to pull it down to see what kind of shape it's in because the sun really did not know. some mothballed it with a 68 327 out of CST pick up. Oklahoma sometimes but very seldom got to run across a 327. Occasionally can find one in a Kansas farm truck but the question is can you get to it fast enough cuz either one of those States or four to six hours just to get to the state line. Oh well for what all that is worth. But I do love talking about 327. They've always been my favorite engine but nowadays an LS engine out of pickup is awfully hard to pass up.
I think you did an excellent job with this video you had a lot of information that not many people understand. I did want to mention people that talk about getting 9000 + RPMs are not talking about the painstaking effort going into Blueprinting the engine, Making sure every piston, every connecting rod and all the components not only measuring as close to exact sizes but weight the same is key along with the small Journal blocks in allowing for such high rev speeds safely without causing engines to blow before their time.
Bought my z in 1976 for $1900.00, now has 73,000 miles and restoring it, got rid of 2 bolt main MO block for a 4 bolt unit in 1980, been in a heated garage in Colorado for 24 years, started right up, no smoke, now I can put all those new parts on her, has L2210. 12-1/2 compression TRW pistons in it, 1/16” rings!
In the early '60s, hot rodders were boring out 283s to 4 inch and also using 327 pistons for performance. The results were called 301s because it was actually 301.59 cubic inches. Chevy decided to call their engine a 302.
I have a '67 z-28 with the 302. The truth, build it for the sound, not the performance. It is one of the best sounding engines ever made. It really starts pulling around the rpm's you normally expect parts to be flying out of the hood. The parts you need to turn it like it wants to turn don't come cheap, and even the good parts don't hold up long turning 9 grand.
Got one in a nostalgia dragster it really doesn't come alive until 5k rpm but it turns 8800 consistently. You're right though not cheap considering it really needs a solid roller and good billet cam core, along with good valves and springs. Even me building the engine in my shop we had around 9k in parts. But like I said its consistent and it's only had 2 refreshes in 8 years.
302 runs like a 2 stroke dirt bike and needs to be run through the gears like that to really rip. Soggy on low end but strong from 4000 on up. It will outrun bigger inch longer stroke small blocks like 350/400 that can't spin like a 302, from 6000 to 8000 the 302 spools up quick.
The 69 DZ motors was a 1178 large journal crank. 67-68 MO, MI 302s was small journal which is the same as a 283. Either way it's a great motor and sound really good.
Great video by the way. One thing I rarely see covered in these videos If You're Building an engine like a 302 or a 327 and you would like to run a really good modern forged crankshaft or forged pistons the price is substantially more expensive than off-the-shelf 350 parts. There are no longer any off-the-shelf 302 or 327 Pistons. I had to go with diamond and have the Piston pin relocated on an off-the-shelf modified piston at a fair bit higher price. I had personal reasons to go with a 327 for my 69 Nova and almost all new part 440 HP solid roller lifter motor will be in the car soon. Just remember 327 and 302 or a fair bit more expensive. And the same Parts in a 350 or 383 will certainly make more horsepower. But at a significantly lower RPM level
Had a 69 Z/28 in the early 70s which was one powerful car. The engine was strong and Chevy had the low 290HP for one reason... lower insurance rates. It also pushed upwards of 360hp, and after I installed headers and had a performance valve job done with a lot of mods to the upper end, the engine builder estimated it was putting out well over 400HP. I never revved it above 6500 RPMs (the red line) much, but I know it could bounce the 140mph speedo at around 7k. I had a Lakewood bell housing with a clutch setup that took awhile to master just the right combo with a 50 lb flywheel. It had a 3.73:1 posi rear end as I never wanted to use it at the strip. With Koni adjustable shocks, it handled well for the time. That motor sounded fantastic thru the turbo Corvair mufflers.
I have a '67 302 block with the correct casting numbers that I bought from a guy that didn't know what he had. But I can't deal with the 11:1 compression pistons that cost $600 to $900 a set depending who you buy them from.I've bought three 283 short blocks at the salvage yard and they all had cast cranks so I'm giving up and gonna sell it to someone with a real Z that wants the correct number block and buy a 350 to put in my Camaro. 350 parts are super cheap.
Really isn't anything wrong with the cast crank if it's in good shape. Set of flat top pistons depending on which cylinder head you use. should keep you in the 10 to one area for compression. you can run on pump gas all day on that. Around Ran my 68 GTO at 10 1/2 on pump fuel for years. (Pre ethanol) era of course I live at 4,000 ft above sea level and usually uphill went uphill sometimes to 7000 and higher elevation. So have modestly reduced compression ratio due to atmospheric pressure.
If you just have to, find a 283 from a truck for a forged crank. Look at the parting line on the flywheel end of the crank eith the glywherl off. If it's narrow and sharp, it's cast. Wide and flat, it's forged.
We have been designing several SBC's using 4 inch bores. The 302 uses a 3 inch stroke. By adding or subtracting 1 inch, the same engine becomes a 402 or 202. 302 is over square and 202 is 2x over square. The 402 is square. Looking at a 502, high torque engine which is under square, but 5 inch stroke in SBC is difficult. A 1 inch spacer between heads and block is possible. All use 6 inch rods.
My dad had a TON of 327's - owner of the vending company next door would swap out engines @ 50,000 miles no matter what. To top it off, he was running propane Built several 302's "back in the day"
The real advantage of the SBC 302 was the high rev screamer. Which is awesome on an oval or road course with long straights but so much is wasted on the street, whereas a 350/383/400+ is much better suited for street when operating at lower rpm’s. The sbc 302 does pair nicely with the power glide though since that transmission comes from the planet Krypton
Some later 283's could be bored out to a 4" bore and back in the day would be called a 301. Same if you mix a 283/327. This started before the "302" was launched and some people still refer to the homemade 4" bore, 3" stroke engine as a 301. Actual displacement is 301.59 ci. 68/69 had a large journal crank and is specific to the 302. Small journal had a slower bearing speed. Oil has a limit, so higher bearing speeds cause the oil to shear and you lose the cushion. This is a big problem in the 455 Pontiac engine which is why it's better to use a 400 block to build a 455 if you want to rev over 5.5-6k rpm consistently. IMO you can get all the high revving fun out of a 327. Heads and intakes that flow well are available in the reasonable price range. You can make anything rev to the moon, but the 327 is a great platform to do it for a reasonable cost. I'm talking a 7-8k rpm screamer. The bigger the displacement the bigger the heads and intake need to get and the higher the price gets. In 1970 the SCCA dropped the homologation rule for the 5.0L displacement and allowed de-stroking production engines so they stopped.
Fun fact about the 1969 dz302. The block itself is physically smaller in a sense than a typical gen 1. If you put a 3.48 stroke into it the connecting rods bolt head will hit flat on bottom of oil pan surface. You have to cut 1/2-3/4 Grove for each rod.
It depends on the serial number theres a few that were known as the 4" bore blocks they used them for all four engines 302 327 350 377 but the performance or racing block they are smaller than the common ones
The Chevy Vega was going to be the most unique for it's time. It was going to get a all alum GM DZ 302 at 11/1, 4 speed Crusher, Posi rear with 4.10 gears, 4 wheel disk, big swaybars, Was to be called the Z-29 Vega (Z-28 was taken). 1 Prototype was made, don't know where it is now. I remember Blue and white striped scheme, some USA thrown on there I believe. Blond fender candy in sequins and Go-Go boots, Torpedos in place, lmao. The gas crunch hit and emission regs popped up, all our hopes of SERIOUS fun with cool shit were dashed. The 302's were a track car, not so much a street warrior per-say, although, they did earn their black stripes on the street. The loved to sing on the track with the solid lifter and big carb. It WAS a challenge to keep a tank of hot fuel in it. I kept a "Green Book" of all the airports with 100 -110 fuel available. I did find a 1959 thick wall 283 complete untouched unopened(until me) for $300, 50k miles. Steel crank is perfect. It keeps looking at me. Iron Eagles or some worked Twitted Wedge heads.
The problem I saw with the 302 is that the 11:1 compression was NOT a problem for pump gas in the late 60's, but it certainly is today. So yes they can be made better today, but part of modern improvements will be just to catch up to loosing out on the benefit of high compression.
What made the 302 perform so well, compared to other Chevy small block engines of the time, was the modern intake manifold and carburetor. The 350 horsepower 327 had an old intake manifold and carbutor from 1962, that wasn't very well design. The 327 hydraulic camshaft wasn't a great design either. The 350hp 327 got a Quadrajet intake and carb in 68. In 1969 the 350 hp 350 came out, with a better hydraulic camshaft. In 1968 Chevy came out with two over the comshafts designed for the 302. One was the, "first design racing camshaft" and the other was the, "improved torque camshaft". The factory 302 camshaft was old 327 camshaft from 1962. In the 1969 model year, Chevy listed over the counter parts for the LT1 370hp 350 engine. This used the 350hp 350 L46 engine, combined with the 302 intake, carb and improved torque solid lifter camshaft. The LT1 350 became a factory installed engine in the 1970 model year. The LT1 camshaft was originally sold as a 302 improved torque camshaft, that was more modern than the factory 302 camshaft. The intake and carb of the 302 made the big difference between the 302 and the other factory engines of the 67-69 model years. The original over the counter 68-69 valve springs for the over the over the counter first design racing camshaft were made of defective steel and would lose tension quickly. The improved torque camshaft, besides being a more modern design, might have been an effort to improve the 302 suitability for automatic transmission, which never made production, most likely due to the production engine size requirement was dropped for 1970.
What id kinda like to know is, what kind of na power and torque that one can squeeze out of a 302 if one were to use modified vortec heads 2.02 valves, etc using also a hyd roller cam with solid roller lifters, and dual quad tunnel ram, but no nitrous or power adders. And modern guts/tech....
I've owned my '67 Z27 for 49 years(350-introduced in Camaro- Camaro exclusive) and drive it almost daily! Also own '68 Cougar, 428 Cobra Jet, which wife's brother bought new in '68! Mercury made 602 big block Cougars too! 244 with the 428 CJ package and 358 with the 427! Love both cars!
Johnie bought a 67 Camaro with a 302 with slanted spark plugs for 900 dollars that even shined . It was blue with a white strip. It did not run but me and Danny put a timing chain and it started up . The chain did not jump but was stretched badly. We did a comp. test and they were all good . We put a 780 Holley and a rebuilt dist. We could not get it to scream . After we gave up it ran for 7 years and he sold it , so who knows how long it ran .
All of the cranks used in the 302’s were forged steel. The difference was in the journal sizes. 1967- ‘68 were small journal, but in 1969 the engines were given the new large journal forged cranks.
Massey Harris combines in the time period had large journal 327 industrial engines. Great place to look for them is a salvage yard for combines in the farm belt.
Id like to get a 3" crank in a 400 block, with 6.125" rods possibly 6.200" rods, and light weight pistons, and aluminum heads zero deck, with 58-60 cc heads 2.08-1.55" valves around 220cc runners, around 11:1-11.5:1, tge aluminum heads should allow it on pump gas, maybe mix with 98-100 octane, half and half run about . 585"-.600" lift roller cam, I have the block and heads! 😆
I raced circle track. We decided to use a large journal 302 because the rules said we would run 10 lbs per cubic inch. Meaning that our 302 would allow us to run a 3020lb car instead of a 3550lb car. You are wrong about the power. We'd reach the speed the 355 would by mid straightaway. We'd come out of the corner at 4500 rpm and end at 7700 rpm. We were the car to beat. Even when we ran tracks with a gear rule, we'd not lose much , they could pull a half a car length down the straightaway but I could fly through the corner much faster being 500 lbs lighter. The 302 is a better motor than the 350 no question.
Stroke has nothing to do with high rpm its all in the vaulve train most importantly the springs that keep you from getting vaulve float. I don't know why everyone thinks its the shorter stroke.... the reason the smaller engines tend to get higher rpm is because you need to spin them faster to get a bigger hp number.
Shorter stroke keeps piston speed down which slows down wear on piston rings and generally equates to a longer life of the bore as well. It's all about piston speed. You can have a large stroke engine rev really high but it's not going to be as reliable as a shorter stroked engine at sustained higher RPM. Say you have a SBC 302 and and SBC 400. The 400s pistons are going to be traveling much faster if both engines are at the same RPM because it requires the piston to cover more ground in the same amount of time. Yes valve train is a very important component but it is not everything to building a high rpm engine, all aspects need to be covered if you're going to spin an engine high. Not just one or the other.
I agree on the valvetrain being the weak point on any SBC motor but the 2.02 intake and 1.60 exhaust valves along w giant springs and a long duration camshaft made all the difference unlike Ford who went for less duration but higher lift on the 302 boss which got beaten time and time again by the dz 302 that video at the end was awesome I haven't heard that sound for so many years now geez they were so awesome for the time of course nowadays an L.S motor a 5.3 with stock heads a cam and an exhaust would be so much cheaper to build and make even more power probably and even live a hell of a lot longer too but that was then and this is now and the dz surely is. A piece of automotive history that will be talked about for yrs to come
Something nobody is thinking about here is the sheer mass of the rotating assembly . The longer the stroke, the heavier the crank is going to be, and it's going to take more time to get to 8000 RPM. compared to the short stroke 302 .It is not so much how high the engine revs up, but how quickly it gets there .
@port nut back in the day a set of 4:56s were everyday street gears , but leaded premium was a whopping $0.32 a gallon ! Our late at night " street " cars ran anywhere from 4:88s to 5:57s , with engines rangng from a .060 over 265 Junior Stock motor to .060 over 427 Rat Motors . The big problem then as now was traction , nobody had a narrowed rear end and wheel tubs , my '55 had radiused rear fenders so I could run anything that I could get my hands on . Big stroke , high torque motors were harder to get hooked up , which is why we ran the short stroke , high winding motors .
I have a DZ in my Camaro that I am currently in the midst of selling. If the buyer doesn't make up his mind soon, it will be on marketplace. Anyhow, if anyone is thinking of building one, you better invest in some very low gears for your rear axel. Once you get the gears you need, and I recommend nothing taller than 4.56, you kind of lose your highway drivability. These engines have about the same torque as a moped. If you think you'll stomp the gas from a dead stop and light the tires up, think again. If I dump the clutch anywhere under the 4 grand, the only smoke l see is coming from the clutch. Sure they rev high, mine has seen the higher side of 7000 many times. If you are going to spend money on a good crankshaft, build a 383 stroker, you will be much happier, be able to do killer burnouts, and those engines are happy with a sensible rear gear. My son has 3.42 in his stroked car, and it will run circles around my 302.
@@timconscciensous3570 my 40 years as a ASE certified technician says differently. Stock 302 Z's in '69 ran 14.80 in the quarter mile. With a roller cam, better intake, open headers, 5.13 gears and slicks mine ran 12.80s launching it at 6000 rpms. It was a matter of time before it exploded. The 377 in the same car with 3.73 gears, full exhaust and street tires runs 12.40s and I can drive it anywhere. Throwing money at a 302 is a waste.
@@kennydemartini2169 If the high RPM of the 302 is the goal without the originality the 377 is the winning combo. 400 block with 69 302/283 crank. Hard to find a large journal forged 283 crank though. Better to order a new forged.
@@BigC8675 I'm all for torque and cubic inches, and I agree, a forged bottom end is the only way to go. I'm thinking of building a 327 now just to see what all the hype is about. I got a pair of AFR heads for it. Getting a forged 327 rotating assembly is getting harder to find.
@@kennydemartini2169 With the right cam and rear gear the 327's sing at higher rpm. I broke several valve springs searching for a couple more hundred RPM back in my street race days in the 90's. HAHA!
I ordered a new '69 Z/28, removed the carb and replaced with '63 Rochester fuel injection. The Z/28 engine was essentially the old Corvette 327 fuelie engine destroked and with carb. It ran better with the F.I. unit, and would turn more rpm. There was also a unique 327 in "66 Novas that was factory rated at 365 hp with a carb.
That was the L76 from the Corvette. It was a carbureted L84 "Fuelie" engine. The L79 327-350 was the highest hp engine available in the 66 Nova and they were hard to run down because they were so light. 3.31 gears was all they really needed on the street.
What's sad is that without a standard transmission and a modified rear suspension and drag slicks whatever car that puny small block is in won't do squat and the heavier the car the worse off it will be. Any midsized car with mild big block engine will trounce it.
Not a single part of a ctual 302 was available in any other chevy engine rockers, pushrods, rods, crank and even the blocks where moly iron. What you can build was the popular 301 which is what you are talking about.
In 69 they quite literally built them out of the exact same block casting they built 350's with for the decade following that. Every part in it other than the pistons was used in other engines right from gm.
Okay lol. Best of luck paying double price for that "010" block because it's a "corvette motor" when it's been decked and the actual information is gone that it came from a pickup truck.
@@jbsmudslide68z33 I no that 283 or 302 crank shaft just wondering on the standard bore if they will just fit right in there of course you’re not gonna find an original set unless you wanna pay top dollar but the new ones could go 30 or 40 over that’s not a real 302 The way this guy says in the video you can just make your own 302 So there has to be a recipe without using original 302 parts because at the end of the day they are a mismatch of a couple of things put into one engine that makes An original factory 302 right
@chicanou-turn5056 I got to agree with you on that. I have found a lot of good deals on 302 Chevy parts. Crankshafts, pistons and even blocks over the years. But I do know what to look for. I been dealing with 302 for years and putting together a 68 302 with factory GM Crossram now.
@@Evil-Jesus LOL - mine already has a 4.56 12 bolt, but only has a 650 DP. I stashed the factory carb. Will an 800 make that much of an improvement? I think the factory was an 830 (or something like that) and I was afraid that it was too big, but I've been wrong before: 😀
Get a late 80's roller 350 block and add a 1994 L99 3 inch stroke crank. I used 6.25 inch rods and 350 pistons designed for 6.00 inch rods. This thing with a mini ram and 276 duration cam made 400 HP on the tires and ran with the AC on. Have fun
I built a small block 327 in 71 with 11.25 pistons and a Dontov 30-30 cam in a 55 Chevrolet ,Edelbrock 2 x 4 with 2 x 600 carters, it would rev past 7000 rpm and tote the front wheels for about 3 car lengths. Broke the motor mounts on the Bellhousing continuously. Put solid steel ones on and stopped that. I was really impressed with that Engine. Clacked like it was coming apart at idle if you can call 1100 rpm a idle but would snap to a really loud roar very quickly. Ported the heads to a round tube Mikey Thompson headers, Had two Edelbrock oval mufflers, it deformed the back of them. Ran good with mufflers but really ran with mufflers off. The good old days.
Hotrodders were building 302's long before Chevy brought out the Z28 302. Yu left out one of the most important parts about building a 302 and that is the choice of heads. For te street the early fuelie heads (1.97" intakes as I remember) are a great choice. My personal favorite SB though was the 350hp 327 found in the 66 Chevy II SS......
I also had a 1969 Z28 - and eventually I went with 4:56's ; as for acceleration, it was way under-geared from the factory.. With the stock 3:73, it had a top speed of about 150 MPH !!! But putting on a set of headers was essential, for the little, screaming 302, to perform to it's full potential !
Yep. Yep! .125 overbored 283 yielded a 4.000" bore coupled with the 3.000" stroke for 301.5936 vs starting with 4.000" bore block and aforementioned 3.000" crank for 301.5936 ci aka 302. Bavk in the day Chevy's Vince Piggins copied the old hot rodder's go-to engine combo from existing parts 327 small journal block and big valve 2.02 /1.60 heads and powerpak 283 crank and BAMM! High revving, good breathing screamer for the original 699 or so 1967 Z/28 homologation cars.
There was only certain 283 blocks that could be bored that much, I can't remember what to look for but there was something in the timing cover area that gave it away. I think they used the same 327 tooling. I had one and it ended up at the scrap yard.
Built a repro 302 50 years ago. Used a 59 Corvette 283 punched out to 4”. The block would take the overbore, I used flat top pistons Fulie heads etc. Ran it in a 39 Ford with 4.11s it weighed 2980 and ran like hell. Used and abused it for over a decade. Still have the car now 350ci
My dad's set up in his 72 vega wagon gt 2300, was a 327 60 over 202 heads solid lift cam 283 crank 4:11 gears on a 10 bolt with ladder bars went from the m22 rock crusher to a 350 3200 stall.. because he missed a gear and lost for the first time.. just Reminiscing l o l
you are telling how to build a 302 from a327 which is true but you forgot to mention that you have to use 302 pistons due to different wrist pin height
i made one for my 69 camaro (not a z/28) a few years ago. i used a 283 forged crank and its original block. i bored it to 4 inch. you have to take out a lot of iron but it works fine.
You could build one......but you have to ask. Why would you? There is a lot of near ROMANCE for the Iconic little Racer that was the 302! That's a fact. Why? TRANS AM!!! The engine powered Mark Donahue to some high profile Championships in his '68 and '69 seasons before Chevrolet pulled out and Donahue left to run an AMC instead. So this alone certainly explains the popularity and ICON status that lives on to this day. In 1967 when Chevy had to build an engine to meet the rule requirements their 327 and new 350 engines already had the 4.0 inch bore and that old school 283 crank length gave them the dimensions required. Engineers threw every trick and part they knew to do at the time at the engine. Free floating wrist pins, all forged low end parts and the best factory heads of the day. Solid lifter cam and pieces like the dual carb cross ram were developed. All of this for use in a racing series that limited entrants to 305cu in or smaller. As a street car motor or drag race engine. This is an IMPOSSIBLE engine to want between the fenders of a Camaro. I can't think of single way to go that makes the 302 a "winner" vs easier and less expensive builds to get to any given ET you might be targeting. The 302 was never installed in any other car beyond the Z/28 for a good reason. It wasn't a good engine vs what could be built when you weren't facing that Trans Am rule book. Today it's really tough to build one. I'd only do it for a factory correct piece of Chevy History. A GOOD '67-'69 real Z/28 Camaro is the only car I'd ever build the engine for and I'd be doing with a clear understanding of how much power I'm giving up after spending the cash and effort vs what I could have built out of a SBC without a 302cu in limitation. Small wonder to me 383 sizes are far more common today when talking about a small block with a 4.0" bore. It takes a pretty serious racing build to coax 500 very peaky HP out a peanut sized 302. You might not care if it makes lousy power under 4,500RPM at a race track. Yet street going, mild mannered, 383 sized engines doing it with big fat torque curves means you can have your cake and eat it too. You can make the same top end power at lower RPM and retain a bunch of tire sheading torque down where you can really use it on the street. Even at the drag strip..... a 383 with a 2,500-3,000RPM stall or clutch dump off the line is going be a lot easier to make reliable than the 302 SCREAMER that winds out to super high RPM and needs a super VIOLENT 4,500 or higher converter or clutch dump to get out off the line. In this you find good arguments for why you so rarely see small displacement SBC. 350 is new "small displacement". I'm seeing a lot of 400 and even 427 Small blocks these days. Roller Cams and aluminum heads with so much more flow than was available back in the day is big part of why the trend to far bigger displacement is happening.
The 302 was definitely the goto around racing rule books, but you had to use the rpm to make it work.. with modest parts it could rev 8000 rpm and be reliable.. where the 350 could not. Side by side, a 302 at 4500rpm could out accelerate a 350 at 3500 rpm on a race track. I raced a 302 on the ovals against the 350.. we selected the 302 on purpose.. for these reasons. Solid lift cam, 11.5:1 compression, heavy valve springs to run up to 8000 rpm.
Okay let me spell this out for you because there were many misnomers to be corrected. Quite simply, the 1967 and 1968 Z28 engines were two bolt main cap 327 blocks with 283 crankshafts. The DZ 302 you are referring to was a one-year-only engine in 1969. They cast a new four bolt main block with larger main journals, produced a new crankshaft of forged steel with larger rod journals to accept the new heavier duty connecting rods. The next year they would add a steel crank with a 3.5 inch stroke and would dub it the LT1 350 which went into the 1970 Z28. Okay?
I actually gave away the mo 2 bolt block for a 70 CRE 300hp 350 4 bolt block out of a monte and put all the guts in it should have kept it but I was single in the Navy and in Washington state with no storage room
I had the privilege of having a 302 with 292 heads solid lift cam 11to 1 compression. My god what a screamer. It was in a 57 bel air manual transmission. I'd kill to have it back!
Building a SBC 302 today is pointless. There are no arguments that are logical. Put all of your dz302 parts in a 350/383/400, it just makes more hp/tq.. Again, take your "correct" dz302 parts, bolt them on a 400 SBC. the 400 will win every race you can imagine
1968 Z-28 motor does not say D.Z. ,they actually say M. O. instead. But in 1969 they say D.Z. on the front of the block,and the crankshaft from the factory!
THE COMMENT ABOUT THE 350 BEING THE KING OF THE SMALL BLOCKS IS HORSE SHID, IN THE 70 s ans 80 s WE RAN SMALL JOURNAL 327s WITH T 400 WITH 3:90 REAR END COMBOS .STREET DRAG RACING FOR YEARS. NEVER NEVER WAS BEAT BUY A 350 CHEVY IN ANYTHING ,
I have a cam'd 302 my dad gave be from his old Chevelle. He moved it into his old Custom Deluxe and had his blood sugar been stable at the time he wouldn't have smashed the side of it into a tree. Engine is in fine condition and I've been babying it for a project. What would you put it into, modern/semi-modern?
I have a couple of 302's one I built one stock, they don't rev because of the short stroke, if that was true the ford 302 would rev like the chevy 302 :)
" back in the day . . . " you used to be able to buy high octane fuel at the pump . by " high octane ' i mean over 102/104 ? something like that . also , you could always go to the local airstrip and buy aviation fuel . . . at least , around here you could . if you could afford it at about double the pump price of premium . yes those were the days . . . my friend .
Ive got at a 69 dz block and piston but no crank and ive got 4 sets of the fuelie heads they called them replacement heads i would like to sale it but not the heads it took me a yr to figure out what the DZ stood for until
I had one. Great engine. Had 12.5 domed pistons,202fueler heads,solid lift cam. Balanced reved to 9500 rpm. Raced it. Fantastic engine.
Bullshit...
You were a lucky man!
302 Had that DZ code in 1969. In 1967 it was a small journal MO or MP code. In 1968 it was a large journal MO code. So keep your eyes open for the codes also. Great video.
A 1969 Z28 302, with a set of headers probably made over 400 HP ; but the sound of that little motor winding out to 7,500 RPM was pure music, that was guaranteed to put a huge smile on your face !!!
😮😊😊
We built a 302 in the 60’s when I was in high school that ran 10 flat and redlined at 10,000 rpm. Sounded sooooo good.
People don't comprehend those motors. They would need to experience it.
Bull crap period ….10.000 rpm
@@welshrarebit9238 yep. 10 grand. 10 flat in the quarter @ 140
@@welshrarebit9238 I am going to say that would be some impressive feat considering racing engines such Nextel Cup, F1, Indy, and even sport bikes have piston speeds that are not exceeding 4800 feet per minute and in the extreme upper end exceeding 5000 feet per second. A Chevy 302 has a 3.0 inch stroke and to turn 10,000 RPM it would have to have the piston traveling at 5000 FPS. The maximum safe piston speed is 4500 (with fully forged and balanced rotating assembly using aluminum rods). This engine would also need to have the valve train components to match this RPM. It is possible, but very unlikely.
@LionWithTheLamb I knew a man by the name of Tom Knolf who raced a '69 Z-28 in the nhra. He dumped the clutch on the car at 10,000 rpm and shifted at 9500 rpm. I've heard many of these stories.
Thanks so much for this review. The 302 little mouse that could...has always been my fav.
1967 blocks (3892657) were MO or MP coded and small journal. 1968 blocks (3914678) were MO but large journal. Only the 1969s were DZ (3956618 or 3970010). Most of the early cars had the 618s and 0010s were mixed in later in the model run.
I seen two DZ marking 68&69 if I’m not mistaken 68 add some small and big journals I’m guessing it was ever left in the dealer that they didn’t sell but large journals for 69👍 but mo & mp are Real 302 sbc some people think if it doesn’t say DZ it’s not real
@@chicanou-turn5056 By the numbers in 67 the 302 was a small journal block (327 block number) and there were about 6 numbers in 67 for a real 302. That was cut back in 68 to 4 small journal 327 block numbers. As far I I know, all the 69 DZ 302s were large journal cranks with a totally different crank then the 67 or 68. Am I wrong in that thinking?
@@hydroy1 you are right majority of the 68 and 69 dz Motors are large journals because it was a 350 / 327 / 302 but there was also small journals that they were making in the factory make 1967 going onto 1968 that were small journals and this is 327 /350/302 probably like the last run of the small journal they got tossed into 1968 and then after that everything went large journal I read about it somewhere also 1967 and I want to say 1968 I might be wrong but there was a 302 mo & mp They were real 302 engine before they put the DZ stamp on it in 1968 at 1969 so early 1967 engines did not have a DZ stamp on them👍 But we’re still real DZ 302 motors
Got a 68 block only, looks as if top of cylinders are slightly chamfered near top. It has been decked and code is not visible anymore. Anybody got any info on this setup?
All 68 Z28's were " MO"...only 69's were dz with 4 bolt mains...
A good friend of mine's Dad was into Drag racing back when i was in School back in the 1960's. They were racing a 1940 Willies the engine was a 283 Bores out to 302 way back in 1963! Dragracers used the 302 long before Chevy made the Z/28.
I built one back in the '70s. Started with a '60 Corvette base 283 engine that had a cracked block, used the a block from a '65 327 Chevelle and a set of flat top pistons and the rest was from the 283 except the intake which was an Edelbrock Torker topped with a Holley 600 double pumper. Put it in a '71 Nova and that thing would flat out run until I let a buddy borrow the car while I was working one night and he blew the engine up trying to street race it.
Bummer! I took a 265 & bored it out to a stock 283 ,powerpack heads ,11to1 pop ups ,400 camshaft,c3bx intake & 650 doublepumper,double pumper,, LOVE SMALLBLOCKS
Thats what I been holding back my LAST NOS 283 steel crank for. But today it's hard to find a standard bore 327 block that doesn't have issues. They all need to be sleeved as most are already +.060 over and need boring. 8 sleeves installed are very pricey when you add aline bore, decking, open up the clearances and everything else needed. I just did a stock rebuild on a 67/ 327 for my daily driver and I dumped $6,500.00 in that puppy real quick for a STOCK rebuild as I don't miss a thing on machine work.
@@hydroy1 A 350 block will also work.
@@hydroy1 I've got a 327 actually I've got at least four of them. You might call me the old bones collector when it comes to 327. This 1327 I first start out with talking about. 1965 Chevy Impala that my uncle bought new and he parked out in the late seventies out at the farm. It was a station wagon he's special order. He wanted hurry up and get those groceries. I don't think it has more than eighty thousand original miles. He just got tired of the old car and park it out at our farm. Said here it is. I used the top end of the engine including four-barrel intake on no 327 that I built and this is all back in the 80s. I still got that wagon with everything but the upper end and front seat. well anyway you're right they're usually worn out three times over. I once drove five or six hours each way just to pick up a 327 that was built by an aircraft mechanic/Machinist. He had passed away and the engine has a few miles on it. I'll have to pull it down to see what kind of shape it's in because the sun really did not know. some mothballed it with a 68 327 out of CST pick up. Oklahoma sometimes but very seldom got to run across a 327. Occasionally can find one in a Kansas farm truck but the question is can you get to it fast enough cuz either one of those States or four to six hours just to get to the state line. Oh well for what all that is worth. But I do love talking about 327. They've always been my favorite engine but nowadays an LS engine out of pickup is awfully hard to pass up.
@@dalesmith561 Yes, if you either use spacers or special extra thick bearings.
MO 302 for 1967 Z28 and early 68 Z28s, after which the DZs started..Great little high RPM screamers.
According to the Z28 guru, Jerry MacNeish " all 68 302 Z28 motors were " MO" engines. Only 69',s were DZ
I think you did an excellent job with this video you had a lot of information that not many people understand. I did want to mention people that talk about getting 9000 + RPMs are not talking about the painstaking effort going into Blueprinting the engine, Making sure every piston, every connecting rod and all the components not only measuring as close to exact sizes but weight the same is key along with the small Journal blocks in allowing for such high rev speeds safely without causing engines to blow before their time.
Bought my z in 1976 for $1900.00, now has 73,000 miles and restoring it, got rid of 2 bolt main MO block for a 4 bolt unit in 1980, been in a heated garage in Colorado for 24 years, started right up, no smoke, now I can put all those new parts on her, has L2210. 12-1/2 compression TRW pistons in it, 1/16” rings!
In the early '60s, hot rodders were boring out 283s to 4 inch and also using 327 pistons for performance.
The results were called 301s because it was actually 301.59 cubic inches. Chevy decided to call their engine a 302.
I have a '67 z-28 with the 302. The truth, build it for the sound, not the performance. It is one of the best sounding engines ever made. It really starts pulling around the rpm's you normally expect parts to be flying out of the hood. The parts you need to turn it like it wants to turn don't come cheap, and even the good parts don't hold up long turning 9 grand.
Got one in a nostalgia dragster it really doesn't come alive until 5k rpm but it turns 8800 consistently. You're right though not cheap considering it really needs a solid roller and good billet cam core, along with good valves and springs. Even me building the engine in my shop we had around 9k in parts. But like I said its consistent and it's only had 2 refreshes in 8 years.
302 runs like a 2 stroke dirt bike and needs to be run through the gears like that to really rip. Soggy on low end but strong from 4000 on up. It will outrun bigger inch longer stroke small blocks like 350/400 that can't spin like a 302, from 6000 to 8000 the 302 spools up quick.
The 69 DZ motors was a 1178 large journal crank. 67-68 MO, MI 302s was small journal which is the same as a 283. Either way it's a great motor and sound really good.
only the 1967 was small journal in 1968 the ho code 302 got the 327 large journal block
Great video by the way. One thing I rarely see covered in these videos If You're Building an engine like a 302 or a 327 and you would like to run a really good modern forged crankshaft or forged pistons the price is substantially more expensive than off-the-shelf 350 parts. There are no longer any off-the-shelf 302 or 327 Pistons. I had to go with diamond and have the Piston pin relocated on an off-the-shelf modified piston at a fair bit higher price. I had personal reasons to go with a 327 for my 69 Nova and almost all new part 440 HP solid roller lifter motor will be in the car soon. Just remember 327 and 302 or a fair bit more expensive. And the same Parts in a 350 or 383 will certainly make more horsepower. But at a significantly lower RPM level
Had a 69 Z/28 in the early 70s which was one powerful car. The engine was strong and Chevy had the low 290HP for one reason... lower insurance rates. It also pushed upwards of 360hp, and after I installed headers and had a performance valve job done with a lot of mods to the upper end, the engine builder estimated it was putting out well over 400HP. I never revved it above 6500 RPMs (the red line) much, but I know it could bounce the 140mph speedo at around 7k. I had a Lakewood bell housing with a clutch setup that took awhile to master just the right combo with a 50 lb flywheel. It had a 3.73:1 posi rear end as I never wanted to use it at the strip. With Koni adjustable shocks, it handled well for the time. That motor sounded fantastic thru the turbo Corvair mufflers.
I had a 69 Z28, had some work done,cam,headwork, also daily driver with 5:38 rear talk about FUN 🤯🤯😎
I'm building one with a vortec 350 roller block and a 4.3l v8 crank, both of which I have
I have a '67 302 block with the correct casting numbers that I bought from a guy that didn't know what he had. But I can't deal with the 11:1 compression pistons that cost $600 to $900 a set depending who you buy them from.I've bought three 283 short blocks at the salvage yard and they all had cast cranks so I'm giving up and gonna sell it to someone with a real Z that wants the correct number block and buy a 350 to put in my Camaro. 350 parts are super cheap.
Really isn't anything wrong with the cast crank if it's in good shape. Set of flat top pistons depending on which cylinder head you use. should keep you in the 10 to one area for compression. you can run on pump gas all day on that. Around Ran my 68 GTO at 10 1/2 on pump fuel for years. (Pre ethanol) era of course I live at 4,000 ft above sea level and usually uphill went uphill sometimes to 7000 and higher elevation. So have modestly reduced compression ratio due to atmospheric pressure.
If you just have to, find a 283 from a truck for a forged crank. Look at the parting line on the flywheel end of the crank eith the glywherl off. If it's narrow and sharp, it's cast. Wide and flat, it's forged.
If you haven't sold it yet what are you wanting for the 302?
I would be interestedvl in buying what you have.
Very cool video, always wanted 1. My buddy has one I rode with him once that thing is nuts.
We have been designing several SBC's using 4 inch bores. The 302 uses a 3 inch stroke. By adding or subtracting 1 inch, the same engine becomes a 402 or 202. 302 is over square and 202 is 2x over square. The 402 is square. Looking at a 502, high torque engine which is under square, but 5 inch stroke in SBC is difficult. A 1 inch spacer between heads and block is possible. All use 6 inch rods.
Built a few back in the 70’s using rpo 302 cams. . Send several built with 30/30 Duntov cams in the late 60’s Screamers!
My dad had a TON of 327's - owner of the vending company next door would swap out engines @ 50,000 miles no matter what. To top it off, he was running propane
Built several 302's "back in the day"
The real advantage of the SBC 302 was the high rev screamer. Which is awesome on an oval or road course with long straights but so much is wasted on the street, whereas a 350/383/400+ is much better suited for street when operating at lower rpm’s. The sbc 302 does pair nicely with the power glide though since that transmission comes from the planet Krypton
Some later 283's could be bored out to a 4" bore and back in the day would be called a 301. Same if you mix a 283/327. This started before the "302" was launched and some people still refer to the homemade 4" bore, 3" stroke engine as a 301. Actual displacement is 301.59 ci.
68/69 had a large journal crank and is specific to the 302.
Small journal had a slower bearing speed. Oil has a limit, so higher bearing speeds cause the oil to shear and you lose the cushion. This is a big problem in the 455 Pontiac engine which is why it's better to use a 400 block to build a 455 if you want to rev over 5.5-6k rpm consistently.
IMO you can get all the high revving fun out of a 327. Heads and intakes that flow well are available in the reasonable price range. You can make anything rev to the moon, but the 327 is a great platform to do it for a reasonable cost. I'm talking a 7-8k rpm screamer. The bigger the displacement the bigger the heads and intake need to get and the higher the price gets.
In 1970 the SCCA dropped the homologation rule for the 5.0L displacement and allowed de-stroking production engines so they stopped.
You are spot on. So many people don't know this!
Fun fact about the 1969 dz302. The block itself is physically smaller in a sense than a typical gen 1. If you put a 3.48 stroke into it the connecting rods bolt head will hit flat on bottom of oil pan surface. You have to cut 1/2-3/4 Grove for each rod.
It depends on the serial number theres a few that were known as the 4" bore blocks they used them for all four engines 302 327 350 377 but the performance or racing block they are smaller than the common ones
The Chevy Vega was going to be the most unique for it's time. It was going to get a all alum GM DZ 302 at 11/1, 4 speed Crusher, Posi rear with 4.10 gears, 4 wheel disk, big swaybars, Was to be called the Z-29 Vega (Z-28 was taken). 1 Prototype was made, don't know where it is now. I remember Blue and white striped scheme, some USA thrown on there I believe. Blond fender candy in sequins and Go-Go boots, Torpedos in place, lmao. The gas crunch hit and emission regs popped up, all our hopes of SERIOUS fun with cool shit were dashed. The 302's were a track car, not so much a street warrior per-say, although, they did earn their black stripes on the street. The loved to sing on the track with the solid lifter and big carb. It WAS a challenge to keep a tank of hot fuel in it. I kept a "Green Book" of all the airports with 100 -110 fuel available. I did find a 1959 thick wall 283 complete untouched unopened(until me) for $300, 50k miles. Steel crank is perfect. It keeps looking at me. Iron Eagles or some worked Twitted Wedge heads.
Nice shirt: maximum approval!
Do the 283 next!
i second that
I'll make sure to put it in my schedule!
The problem I saw with the 302 is that the 11:1 compression was NOT a problem for pump gas in the late 60's, but it certainly is today. So yes they can be made better today, but part of modern improvements will be just to catch up to loosing out on the benefit of high compression.
Used to run 9 seconds quarter mile
What made the 302 perform so well, compared to other Chevy small block engines of the time, was the modern intake manifold and carburetor. The 350 horsepower 327 had an old intake manifold and carbutor from 1962, that wasn't very well design. The 327 hydraulic camshaft wasn't a great design either. The 350hp 327 got a Quadrajet intake and carb in 68. In 1969 the 350 hp 350 came out, with a better hydraulic camshaft. In 1968 Chevy came out with two over the comshafts designed for the 302. One was the, "first design racing camshaft" and the other was the, "improved torque camshaft". The factory 302 camshaft was old 327 camshaft from 1962. In the 1969 model year, Chevy listed over the counter parts for the LT1 370hp 350 engine. This used the 350hp 350 L46 engine, combined with the 302 intake, carb and improved torque solid lifter camshaft. The LT1 350 became a factory installed engine in the 1970 model year. The LT1 camshaft was originally sold as a 302 improved torque camshaft, that was more modern than the factory 302 camshaft. The intake and carb of the 302 made the big difference between the 302 and the other factory engines of the 67-69 model years. The original over the counter 68-69 valve springs for the over the over the counter first design racing camshaft were made of defective steel and would lose tension quickly. The improved torque camshaft, besides being a more modern design, might have been an effort to improve the 302 suitability for automatic transmission, which never made production, most likely due to the production engine size requirement was dropped for 1970.
You got great knowledge, please sharing!
What id kinda like to know is, what kind of na power and torque that one can squeeze out of a 302 if one were to use modified vortec heads 2.02 valves, etc using also a hyd roller cam with solid roller lifters, and dual quad tunnel ram, but no nitrous or power adders. And modern guts/tech....
I love your program
They made 602 z/28's in 67,I know because I owned 1 and a dz 302 I put in a stripped out 70 camaro
I've owned my '67 Z27 for 49 years(350-introduced in Camaro- Camaro exclusive) and drive it almost daily! Also own '68 Cougar, 428 Cobra Jet, which wife's brother bought new in '68! Mercury made 602 big block Cougars too! 244 with the 428 CJ package and 358 with the 427! Love both cars!
Johnie bought a 67 Camaro with a 302 with slanted spark plugs for 900 dollars that even shined . It was blue with a white strip. It did not run but me and Danny put a timing chain and it started up . The chain did not jump but was stretched badly. We did a comp. test and they were all good . We put a 780 Holley and a rebuilt dist. We could not get it to scream . After we gave up it ran for 7 years and he sold it , so who knows how long it ran .
Angle plug heads are aftermarket chevy heads
Score
@@Jack-jw8eh Never saw a 375hp 350
Built an LS 302. Most Wicked Engine I ever built. 10k R.P.M. all day.
the cam had late intake valve closing to use the 11/1 pistions , i put an ls3 in my 69RS Z/28
You can just use longer rods and shorter pistons to get same results say 3.50 crank with 6.100 rods and still get more torque and high rpms
D z 302 also had steel crankshafts
All of the cranks used in the 302’s were forged steel. The difference was in the journal sizes. 1967- ‘68 were small journal, but in 1969 the engines were given the new large journal forged cranks.
@@micahcastillo9113 only 67 were small journal
great info --would enjoy building one --the cheaper version anyway
Builda gen 2 LT with the 5.7 and its little brother 4.3L as it has a 3” stroke .
My 1968 Z28 302 put out 350 hp
want to have some high RPM fun build a 400 block with a 3inch stroke and make a 327 the hard way. It revs like a 302 but more inches for torque.
Bad ass engine
This is the time chevy out done ford Dz 302 is a legend
Not so fast... boss 302 makes more power with less cam and compression. About 25 more... 350 vs 375 on the dyno.
Massey Harris combines in the time period had large journal 327 industrial engines. Great place to look for them is a salvage yard for combines in the farm belt.
Are these the same as the gm302's that cam out of the M211 military trucks?
How about why Chevy with 302 and the 402 3 years each but what else about these two engines .
I had one with twin turbos used a avgas 120
And I'm also trying to sell the Vega with everything that goes with it including fiber glass front end
Id like to get a 3" crank in a 400 block, with 6.125" rods possibly 6.200" rods, and light weight pistons, and aluminum heads zero deck, with 58-60 cc heads 2.08-1.55" valves around 220cc runners, around 11:1-11.5:1, tge aluminum heads should allow it on pump gas, maybe mix with 98-100 octane, half and half run about . 585"-.600" lift roller cam, I have the block and heads! 😆
I can't even imagine what that would do!
Sounds like it would be one of a kind
302..513 gears ,Low 10's 🙂
Lol
I raced circle track. We decided to use a large journal 302 because the rules said we would run 10 lbs per cubic inch. Meaning that our 302 would allow us to run a 3020lb car instead of a 3550lb car. You are wrong about the power. We'd reach the speed the 355 would by mid straightaway. We'd come out of the corner at 4500 rpm and end at 7700 rpm. We were the car to beat. Even when we ran tracks with a gear rule, we'd not lose much , they could pull a half a car length down the straightaway but I could fly through the corner much faster being 500 lbs lighter. The 302 is a better motor than the 350 no question.
Interesting
Stroke has nothing to do with high rpm its all in the vaulve train most importantly the springs that keep you from getting vaulve float. I don't know why everyone thinks its the shorter stroke.... the reason the smaller engines tend to get higher rpm is because you need to spin them faster to get a bigger hp number.
Shorter stroke keeps piston speed down which slows down wear on piston rings and generally equates to a longer life of the bore as well. It's all about piston speed. You can have a large stroke engine rev really high but it's not going to be as reliable as a shorter stroked engine at sustained higher RPM. Say you have a SBC 302 and and SBC 400. The 400s pistons are going to be traveling much faster if both engines are at the same RPM because it requires the piston to cover more ground in the same amount of time. Yes valve train is a very important component but it is not everything to building a high rpm engine, all aspects need to be covered if you're going to spin an engine high. Not just one or the other.
I agree on the valvetrain being the weak point on any SBC motor but the 2.02 intake and 1.60 exhaust valves along w giant springs and a long duration camshaft made all the difference unlike Ford who went for less duration but higher lift on the 302 boss which got beaten time and time again by the dz 302 that video at the end was awesome I haven't heard that sound for so many years now geez they were so awesome for the time of course nowadays an L.S motor a 5.3 with stock heads a cam and an exhaust would be so much cheaper to build and make even more power probably and even live a hell of a lot longer too but that was then and this is now and the dz surely is. A piece of automotive history that will be talked about for yrs to come
Something nobody is thinking about here is the sheer mass of the rotating assembly . The longer the stroke, the heavier the crank is going to be, and it's going to take more time to get to 8000 RPM. compared to the short stroke 302 .It is not so much how high the engine revs up, but how quickly it gets there .
@@bobbrinkerhoff3592 You're right, that was the thinking at the time but as we have all found, Torque is what wins more times than RPM.
@port nut back in the day a set of 4:56s were everyday street gears , but leaded premium was a whopping $0.32 a gallon ! Our late at night " street " cars ran anywhere from 4:88s to 5:57s , with engines rangng from a .060 over 265 Junior Stock motor to .060 over 427 Rat Motors . The big problem then as now was traction , nobody had a narrowed rear end and wheel tubs , my '55 had radiused rear fenders so I could run anything that I could get my hands on . Big stroke , high torque motors were harder to get hooked up , which is why we ran the short stroke , high winding motors .
I have a DZ in my Camaro that I am currently in the midst of selling. If the buyer doesn't make up his mind soon, it will be on marketplace. Anyhow, if anyone is thinking of building one, you better invest in some very low gears for your rear axel. Once you get the gears you need, and I recommend nothing taller than 4.56, you kind of lose your highway drivability. These engines have about the same torque as a moped. If you think you'll stomp the gas from a dead stop and light the tires up, think again. If I dump the clutch anywhere under the 4 grand, the only smoke l see is coming from the clutch. Sure they rev high, mine has seen the higher side of 7000 many times. If you are going to spend money on a good crankshaft, build a 383 stroker, you will be much happier, be able to do killer burnouts, and those engines are happy with a sensible rear gear. My son has 3.42 in his stroked car, and it will run circles around my 302.
You did something seriously wrong my friend. I had a 302 in a 57 chevy and beat a gto judge!
@@timconscciensous3570 my 40 years as a ASE certified technician says differently. Stock 302 Z's in '69 ran 14.80 in the quarter mile. With a roller cam, better intake, open headers, 5.13 gears and slicks mine ran 12.80s launching it at 6000 rpms. It was a matter of time before it exploded. The 377 in the same car with 3.73 gears, full exhaust and street tires runs 12.40s and I can drive it anywhere. Throwing money at a 302 is a waste.
@@kennydemartini2169 If the high RPM of the 302 is the goal without the originality the 377 is the winning combo. 400 block with 69 302/283 crank. Hard to find a large journal forged 283 crank though. Better to order a new forged.
@@BigC8675 I'm all for torque and cubic inches, and I agree, a forged bottom end is the only way to go. I'm thinking of building a 327 now just to see what all the hype is about. I got a pair of AFR heads for it. Getting a forged 327 rotating assembly is getting harder to find.
@@kennydemartini2169 With the right cam and rear gear the 327's sing at higher rpm. I broke several valve springs searching for a couple more hundred RPM back in my street race days in the 90's. HAHA!
I ordered a new '69 Z/28, removed the carb and replaced with '63 Rochester fuel injection. The Z/28 engine was essentially the old Corvette 327 fuelie engine destroked and with carb. It ran better with the F.I. unit, and would turn more rpm. There was also a unique 327 in "66 Novas that was factory rated at 365 hp with a carb.
That was the L76 from the Corvette. It was a carbureted L84 "Fuelie" engine. The L79 327-350 was the highest hp engine available in the 66 Nova and they were hard to run down because they were so light. 3.31 gears was all they really needed on the street.
67 302's did not have the dz code.....do your research.....but the internet lies.....
Are all 283 cranks forged
What's the story with the 68 z behind you
What's sad is that without a standard transmission and a modified rear suspension and drag slicks whatever car that puny small block is in won't do squat and the heavier the car the worse off it will be. Any midsized car with mild big block engine will trounce it.
Not always
I would love to talk to you more about it
Not a single part of a ctual 302 was available in any other chevy engine rockers, pushrods, rods, crank and even the blocks where moly iron. What you can build was the popular 301 which is what you are talking about.
In 69 they quite literally built them out of the exact same block casting they built 350's with for the decade following that. Every part in it other than the pistons was used in other engines right from gm.
@@HSTvids357 do some reasurch other than the internet you might learn something caus you are wrong.
Okay lol. Best of luck paying double price for that "010" block because it's a "corvette motor" when it's been decked and the actual information is gone that it came from a pickup truck.
So can you put the 302 pistons right in at 3:27 block or do you have to have a board
Same bore
Just got to change the crankshaft, rods (unless you have a real nice set of floating rods) and the pistons and your good to go.
@@jbsmudslide68z33 I no that 283 or 302 crank shaft just wondering on the standard bore if they will just fit right in there of course you’re not gonna find an original set unless you wanna pay top dollar but the new ones could go 30 or 40 over that’s not a real 302 The way this guy says in the video you can just make your own 302 So there has to be a recipe without using original 302 parts because at the end of the day they are a mismatch of a couple of things put into one engine that makes An original factory 302 right
@chicanou-turn5056 I got to agree with you on that. I have found a lot of good deals on 302 Chevy parts. Crankshafts, pistons and even blocks over the years. But I do know what to look for. I been dealing with 302 for years and putting together a 68 302 with factory GM Crossram now.
And did not know that it is super rare
aluminum heads 11.1 no problem
67 302's were YZ code 68 & 69 were DZ code.
67 and 68 is MO code.
Although a high winding 302 and 4 spd lots of fun
And rods
Dam does this ever stop with the Freemason hand gestures???? 😒
I'd rather have more cubes so I'd take a 1970 LT1 350 over the DZ 302.
My DZ would smoke any Small block and most big boys
@@Evil-Jesus Is your DZ stock? My DZ sounds and runs great, my it is not the fastest one out there. Would like to hear more about your setup.
@@v8chevy788 Gotta give it a hot ignition 800 DP and 4:56's Its not a bottom end monster that's for sure
@@Evil-Jesus LOL - mine already has a 4.56 12 bolt, but only has a 650 DP. I stashed the factory carb. Will an 800 make that much of an improvement? I think the factory was an 830 (or something like that) and I was afraid that it was too big, but I've been wrong before: 😀
@@v8chevy788 780, 800 will wake her up, 2 660's even better lol I put a pair of 600's drove it around the block and took them off
They weren't impressive on the streets. More for road racing.
67 and 68 were small journal, 69 was large.
nope only 1967 was small journal
@@bigdon2241 Correct,look in the parts catalog for bearings and it shows that's true.
@@bigdon2241 62/66 are small journals
@@glenbiliti7076 no small journal last year 1967 in 1968 all large journal
67 was small 68 and 9 were large
The Boss302 spanked the DZ302
Dilusional! The chevy 302 won the trans am race two years in a row!
Get a late 80's roller 350 block and add a 1994 L99 3 inch stroke crank. I used 6.25 inch rods and 350 pistons designed for 6.00 inch rods. This thing with a mini ram and 276 duration cam made 400 HP on the tires and ran with the AC on. Have fun
What kind of heads did you use? I bet with the Vortec heads that would be a mean little engine! What kind of RPM you pull out of it?
Yes !!
I built a small block 327 in 71 with 11.25 pistons and a Dontov 30-30 cam in a 55 Chevrolet ,Edelbrock 2 x 4 with 2 x 600 carters, it would rev past 7000 rpm and tote the front wheels for about 3 car lengths. Broke the motor mounts on the Bellhousing continuously. Put solid steel ones on and stopped that. I was really impressed with that Engine. Clacked like it was coming apart at idle if you can call 1100 rpm a idle but would snap to a really loud roar very quickly. Ported the heads to a round tube Mikey Thompson headers, Had two Edelbrock oval mufflers, it deformed the back of them. Ran good with mufflers but really ran with mufflers off. The good old days.
Awesome story man. It’s ones like this, that only make my hot rod fever worse lol. Hope you can have another badass street machine someday soon!
Hotrodders were building 302's long before Chevy brought out the Z28 302. Yu left out one of the most important parts about building a 302 and that is the choice of heads. For te street the early fuelie heads (1.97" intakes as I remember) are a great choice. My personal favorite SB though was the 350hp 327 found in the 66 Chevy II SS......
We generally called them 301s though. (301.6 actual displacement).
@@jamesgiddings260generally?
I had a 1969 Z. The very best performance add-on was a 4.88 gear. Talk about a red light bandit, color me gone.
I also had a 1969 Z28 - and eventually I went with 4:56's ; as for acceleration, it was way under-geared from the factory..
With the stock 3:73, it had a top speed of about 150 MPH !!!
But putting on a set of headers was essential, for the little, screaming 302, to perform to it's full potential !
Guys racing modifieds were building 302's long before the Z28 came out.
Yep. Yep! .125 overbored 283 yielded a 4.000" bore coupled with the 3.000" stroke for 301.5936 vs starting with 4.000" bore block and aforementioned 3.000" crank for 301.5936 ci aka 302. Bavk in the day Chevy's Vince Piggins copied the old hot rodder's go-to engine combo from existing parts 327 small journal block and big valve 2.02 /1.60 heads and powerpak 283 crank and BAMM! High revving, good breathing screamer for the original 699 or so 1967 Z/28 homologation cars.
yes we called them 301
There was only certain 283 blocks that could be bored that much, I can't remember what to look for but there was something in the timing cover area that gave it away. I think they used the same 327 tooling. I had one and it ended up at the scrap yard.
@@stevenbelue5496 the 1957 was the block
Built a repro 302 50 years ago. Used a 59 Corvette 283 punched out to 4”. The block would take the overbore, I used flat top pistons Fulie heads etc.
Ran it in a 39 Ford with 4.11s it weighed 2980 and ran like hell. Used and abused it for over a decade. Still have the car now 350ci
My dad's set up in his 72 vega wagon gt 2300, was a 327 60 over 202 heads solid lift cam 283 crank 4:11 gears on a 10 bolt with ladder bars went from the m22 rock crusher to a 350 3200 stall.. because he missed a gear and lost for the first time.. just Reminiscing l o l
It was a smokin' radical little engine! Almost unknown 'cause of a "competitors" 302. Almost too high strung for the street.
you are telling how to build a 302 from a327 which is true but you forgot to mention that you have to use 302 pistons due to different wrist pin height
i made one for my 69 camaro (not a z/28) a few years ago. i used a 283 forged crank and its original block. i bored it to 4 inch. you have to take out a lot of iron but it works fine.
You could build one......but you have to ask. Why would you? There is a lot of near ROMANCE for the Iconic little Racer that was the 302! That's a fact. Why? TRANS AM!!! The engine powered Mark Donahue to some high profile Championships in his '68 and '69 seasons before Chevrolet pulled out and Donahue left to run an AMC instead. So this alone certainly explains the popularity and ICON status that lives on to this day. In 1967 when Chevy had to build an engine to meet the rule requirements their 327 and new 350 engines already had the 4.0 inch bore and that old school 283 crank length gave them the dimensions required. Engineers threw every trick and part they knew to do at the time at the engine. Free floating wrist pins, all forged low end parts and the best factory heads of the day. Solid lifter cam and pieces like the dual carb cross ram were developed. All of this for use in a racing series that limited entrants to 305cu in or smaller. As a street car motor or drag race engine. This is an IMPOSSIBLE engine to want between the fenders of a Camaro. I can't think of single way to go that makes the 302 a "winner" vs easier and less expensive builds to get to any given ET you might be targeting. The 302 was never installed in any other car beyond the Z/28 for a good reason. It wasn't a good engine vs what could be built when you weren't facing that Trans Am rule book. Today it's really tough to build one. I'd only do it for a factory correct piece of Chevy History. A GOOD '67-'69 real Z/28 Camaro is the only car I'd ever build the engine for and I'd be doing with a clear understanding of how much power I'm giving up after spending the cash and effort vs what I could have built out of a SBC without a 302cu in limitation. Small wonder to me 383 sizes are far more common today when talking about a small block with a 4.0" bore. It takes a pretty serious racing build to coax 500 very peaky HP out a peanut sized 302. You might not care if it makes lousy power under 4,500RPM at a race track. Yet street going, mild mannered, 383 sized engines doing it with big fat torque curves means you can have your cake and eat it too. You can make the same top end power at lower RPM and retain a bunch of tire sheading torque down where you can really use it on the street. Even at the drag strip..... a 383 with a 2,500-3,000RPM stall or clutch dump off the line is going be a lot easier to make reliable than the 302 SCREAMER that winds out to super high RPM and needs a super VIOLENT 4,500 or higher converter or clutch dump to get out off the line. In this you find good arguments for why you so rarely see small displacement SBC. 350 is new "small displacement". I'm seeing a lot of 400 and even 427 Small blocks these days. Roller Cams and aluminum heads with so much more flow than was available back in the day is big part of why the trend to far bigger displacement is happening.
Correct! In '70 SCCA allowed destroking, hence the introduction of the LT-1 350 in the '70-1/2 model Z-28.
The 302 was definitely the goto around racing rule books, but you had to use the rpm to make it work.. with modest parts it could rev 8000 rpm and be reliable.. where the 350 could not. Side by side, a 302 at 4500rpm could out accelerate a 350 at 3500 rpm on a race track. I raced a 302 on the ovals against the 350.. we selected the 302 on purpose.. for these reasons. Solid lift cam, 11.5:1 compression, heavy valve springs to run up to 8000 rpm.
Okay let me spell this out for you because there were many misnomers to be corrected. Quite simply, the 1967 and 1968 Z28 engines were two bolt main cap 327 blocks with 283 crankshafts. The DZ 302 you are referring to was a one-year-only engine in 1969. They cast a new four bolt main block with larger main journals, produced a new crankshaft of forged steel with larger rod journals to accept the new heavier duty connecting rods. The next year they would add a steel crank with a 3.5 inch stroke and would dub it the LT1 350 which went into the 1970 Z28. Okay?
I actually gave away the mo 2 bolt block for a 70 CRE 300hp 350 4 bolt block out of a monte and put all the guts in it should have kept it but I was single in the Navy and in Washington state with no storage room
68 was large journal, no 283 crank - it was specially made for the 302
Very correct. Dz was completely original 1 year only
You learn something new everyday. Thank you.
I had the privilege of having a 302 with 292 heads solid lift cam 11to 1 compression. My god what a screamer. It was in a 57 bel air manual transmission. I'd kill to have it back!
Building a SBC 302 today is pointless. There are no arguments that are logical. Put all of your dz302 parts in a 350/383/400, it just makes more hp/tq.. Again, take your "correct" dz302 parts, bolt them on a 400 SBC. the 400 will win every race you can imagine
1968 Z-28 motor does not say D.Z. ,they actually say M. O. instead. But in 1969 they say D.Z. on the front of the block,and the crankshaft from the factory!
I Have 1 in A 1981 Cutlass Supreme
Building a 327 with a steel crank with vortec heads and intake full roller set up😁
THE COMMENT ABOUT THE 350 BEING THE KING OF THE SMALL BLOCKS IS HORSE SHID,
IN THE 70 s ans 80 s WE RAN SMALL JOURNAL 327s WITH T 400 WITH 3:90 REAR END COMBOS .STREET DRAG RACING FOR YEARS.
NEVER NEVER WAS BEAT BUY A 350 CHEVY IN ANYTHING ,
I never got beat by a 350 either for that matter, any chevy on the street. 351 Cleveland in a 66 mustang gave the Chevy boys fits....
I would have to agree. People just don't know.
I have a cam'd 302 my dad gave be from his old Chevelle. He moved it into his old Custom Deluxe and had his blood sugar been stable at the time he wouldn't have smashed the side of it into a tree. Engine is in fine condition and I've been babying it for a project. What would you put it into, modern/semi-modern?
I have a couple of 302's one I built one stock, they don't rev because of the short stroke, if that was true the ford 302 would rev like the chevy 302 :)
I believe the biggest difference between the Ford and Chev 302 Engines, is in the profile of the cams !
@@georgehill7881 cam profile, compression ratio crank weight rod/ piston weight , bunch of things different and the chevy 302 don't split in half
Ford 302s are pure shit! Good boat anchor!
" back in the day . . . "
you used to be able to buy high octane fuel at the pump . by " high octane ' i mean over 102/104 ? something like that .
also , you could always go to the local airstrip and buy aviation fuel . . . at least , around here you could . if you could afford it at about double the pump price of premium .
yes those were the days . . . my friend .
Ive got at a 69 dz block and piston but no crank and ive got 4 sets of the fuelie heads they called them replacement heads i would like to sale it but not the heads it took me a yr to figure out what the DZ stood for until
11.1 will run on pump you just need an in cab ignition adjuster or efi
Aha! So thats what i heard yrs ago and wondered what he had in there. It sounded more like some high powered sewing machine, LOL!