BIG BORE VS BIG STROKE-372 VS 383-WHICH SBC STROKER DOES IT BEST? BONUS TEST-302 VS 347 FORD
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- Опубликовано: 6 июл 2024
- WHICH ONE MAKES MORE POWER, BIG BORE OR BIG STROKE? DOES A 372/377 MAKE MORE POWER THAN A 383? DOES THE 4.125-INCH BORE ON THE 372 MAKE THE HEADS FLOW BETTER? WILL THE INCREASED HEAD FLOW TRANSLATE TO MORE POWER? DOES A BIGGER MOTOR MAKE MORE POWER? WHY IS THE 383 STROKER SO POPULAR? DO I NEED AN AFTER MARKET BLOCK TO MAKE A 377? CAN I USE A 400 BLOCK? BONUS TEST-302 VS 347 WITH THE STOCK HEADS, CAM AND INTAKE. WILL THE EXTRA CUBES STILL MAKE MORE TORQUE WHEN CHOKED OFF WITH THE STOCK INDUCTION SYSTEM? CHECK OUT THE VIDEO FOR FULL DYNO RESULTS.
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I've built both a 383 and a 372. Same cam in both, same World Products heads. Hey, I worked at a auto parts store at the time. Maybe more torque below the 4500 mark for the 383, but a fair amount more power above 4500 for the shorter stroke. The only explanation at the time was the bigger bore made better use of "average" heads with no issues with flow around the valves near the cylinder walls. I actually liked the 372 better, but when I did both engines the idea of the 383 was fairly new and some guys were having problems with side load on what you'd have to call crappy pistons. A friend built a 383 as well, and he came up with the most common sense outlook on both engines. Build a 383, put it in a truck... Build a 372, put it in a non heavy car with some decent rear end gear, and enjoy the top end. Or build an all out effort (read as All Your Money) of either and never notice the difference.
Or just build a 406 and kick both motor's butts.
Long stroke causes higher piston speed, air has to travel faster in a 383 , which it can’t. The larger bore unshrouds the valve for more flow. Low torque on the longer bore is leverage, but it can’t inherently breath as well. Shame it doesn’t have 14:1 and water/ meth .
@@dennisford2000 I figured a lot of Richard's viewers already knew the leverage of the stroker on the crank, not just the displacement versus unshrouding the valve. There is always a trade off somewhere, and sometimes the trade off is smaller.
@@corvettejohn4507this is what i told my friend several years ago when he wanted me to build him a 383 "stroker". He was in love with that word. I told him do a 406 & tell everyone its a 383 "stroker" if u just want to use that word cause it will kick the shit out of a 383
Yep. I'm new, like what you're doing Richard. Appreciate response
This comparison is a great example of why we should be using area under the curve instead of just peak numbers.
and why I provide the curves
@richardholdener1727 that was more of a comment on the dyno world in general, not a specific criticism of your methodology. You're one of the few that even discusses the curves on your results. So many just just display peak numbers and judge engines by that.
That said, it would be easy to import that data into a spreadsheet and have a macro that calculates and displays the actual area under the curve vs just the peak numbers or just the curves.
Yet you hardly ever see that. It should be a standard part of the dyno output IMO.
the curves tell you the story
Uncle swore by the 377(400block-350 crank) in the sprintcar. Did not need gobs of tq, but the extended rpm help with tractable tq for a very light car.
The tow/hauler ran a 383-more drivable tq. Both motors were very different tho. But who doesn't like a rooting tootin gross pollutin high revin sbc?
377 was also bae in sand drags and sprint boats! Amazing engine!
I think the 302/347 comparison was more helpful because it was a direct comparison with no variation between cam grinds, heads, intakes etc. Both the 383 and the 372 would be fun engines, but it wasn’t apples to apples enough to really gain any insight into differences between the two engines. Lift and cam timing at 050 were similar, but we don’t know much about the rest of the profile. The heads and intake may have flowed similarly, but at these power levels lots of little variables can stack up. The higher torque and better midrange for the 383 are classic benefits of a tighter LSA and more displacement, though
Different displacement require different lsa, so even the cam doesn't do any justice
I'm thinking same. Close to specs, tells nothing about the true character of each motor. Different lobe profiles, LSA, and duration are the bulk of his test results.
But, he don't care really. Its about views and comments. $$$$$ = views and comments, good or bad.
A neat comparison for the bore/stroke comparison would be, cam and intake each combo for the inherent sweet spots. Go for 500+torque and 5700rpm redline on the 383. Go for 500hp and 6500+rpm on the377. Use formula for a car and see which is faster. Of course some like brute torque and others like banging gears at 7000rpm. It's really all about flavor, yes?? Im just a car dude. Thank you for videos and community interaction. Be well everybody.
I’ve been requesting this for years. Thank you
Bore = potential valve area. Stroke = length of the lever.
Long stroke means more piston speed, which will help at lower rev's. The Ford numbers would have been very interesting from 1000 rpm lower, but unfortunately that's not how it happened. Good information Richard. Thanks very much
I have a 1963 Ford Falcon that came with 260. I now have 302 with 1969 351W heads. A 351 will not fit in the engine compartment without serious modifications. So a 347 might be good. But the 302 is sufficient.
I have the same problem in my 1960 falcon, I'm running OEM exhaust manifolds just so it fits.
I’ve always thought of an experiment like this with the LS platform.
Comparing a 5.7L ls1 with an “LS7” based engine destroked to 5.7L with the 4.8 rotating assembly. Both of these engines displacements and compression ratios are both within 1%! With the same cylinder head / valvetrain it would be interesting to see how they compare!
A few months ago he did a destroked LS3 video, 4.8 crank in a 6.2 block. LS 327 basically
Thanks Richard. The charts tell me a stroker wouldn't be a waste of time with stock heads if just for a nice street driver. I learned something today 👍
N thanks Richard love all your testing
On the SBCs the stroke swallowed the duration up on the 383 so it did better lower . The narrower lsa also helped the 383 more due to stroke . But truthfully both lsa were too wide .
106
106 is crankshaft centerline
Re 372 4.125x3.48 vs 383 4.03x3.75
I tune lots of bike engines. I see both configurations in similar displacements.
Torque falls off more the more over square. Horsepower goes up from breathing and more esoteric things like sqirl and squish.
I would really love to have my 5.7 Hemi stroked, some Edelbrock heads, and some headers for my 2005 Daytona edition RAM 1500. I don't want a different camshaft, and I don't want a different intake manifold. I just want more torque with a little more airflow on the exhaust side. Nothing super fancy. Just a stroker crankshaft with the appropriate connecting rods and pistons, new heads, and headers.
With regards to stroke vs. bore, it's all about use case.
I have a 3/4 Ton Suburban, and not long after I got it, I replaced the 350 with a GMPP HT383E. I have zero regrets about that choice. It didn't just give me more power, but it gave it to me where I especially wanted it, down low. It gets that heavy truck moving so much easier, and it's a tow beast a well. Plus, it will power through heavy snow and dirt with ease.
That said, back in my youth I had a buddy with a really lightweight Nova with a 327, and that high RPM power curve was perfect. I'd love to see it scream with a high revving 372 with 2.02/1.60 valved heads.
My thoughts on the 372 v 383: With the bigger bore, the 372 did better on the top end because the larger bore allowed for better airflow. The reason why the 383 had more torque was because of the displacement difference. I'd personally take either one of them, but there really is no replacement for displacement, so the 383 wins in my book. having better torque all the way down the graph in the area where you need it makes a lot of sense to me.
You said it brother
I would agree. I'm not a fan of giving up 30-40 lb-ft in the midrange to net 10-15 hp up top on a street engine. Though if the intended use is street/strip getting significant track time then I'd porobably go with the 372 would make up for the difference in the low to mid by shedding a little weight.
How does a big bore allow for more airflow?
The heads either flow enough air or they don’t. Atmospheric pressure is trying to fill each cylinder volume based on a differential. The pressure doesn’t know if it’s a long stoke or wide bore.
The big bore should allow high revs and then match it with a cam with peak higher up. You should also be able to have bigger valves without shrouding.
And in theory you should be able to put more timing in as the flame front has greater distance to travel greater.
This comparison did nothing. You should build these engines differently.
Depends on where you need it. The torque below the curve won't matter in an all out, well hooked up setup.
@@zztop7306 That’s a given.
You can’t work out which is best when they will do different things in different scenarios.
The point of the video could of been to show what could be done with each, safely, but it didn’t do that.
You would put the 372 in a lighter car and build it for race.
You would put the 383 in a heavier car and run it on the street.
You can’t conclude one is better than the other. Just that they are better at different things.
Second half of the video was great! I have a 305 and thinking about making it a 334 and leaving the heads, intake, and carb the same but wasn't sure if it would work. This pretty much confirms it would and would give the gains in low end power I am looking for. Most bolt on power only helps at the top end and hurts the low end. Spinning an engine over 5k rpm doesn't have much real world application.
5.0L Ford was ~9:1 compression. The 347 stroker with flattops has ~10.25:1 cr. Big difference in cr... in addition to the longer stroke.
Did a 5.0 HO swap on my purchased new 1987 TBird Turbocoupe. Super budget I torque ported the stock heads and intake, ran an E303 cam and 1.5" shorty headers. Never replaced the stock valve springs (mistake). Made 314tq at 3500rpm and 250hp at only 4700rpm on a Dynojet. As for the low power rpm I never replaced the valve springs or headers but did try an Edelbrock intake with no improvement. Interesting how it compared to the baseline motor above. Was a ton of fun as a street car!
adding stroke not only increases some displacement, but it also increases the leverage of the crank. the pistons are now pushing down on a LONGER torque arm.
Also on a small block chevy, if you put a 3.75 stroke crank in a 4.125 bore block you will make more power than both the 383 and 377. I think they might have made an engine with that combo.
That long/short stroke graph looks like every test I've ever done, though being in the UK our No's are on another scale.
90% of the motors we work with wouldn't make 500hp with boost, nitrous and race fuel. 🙂 Or if they did, the pistons would go down, and keep going . Our stuff is just so much smaller, a 2Ltr is now regarded as a big motor
I built a 372 back in '75 for my sprint car. It was the least expensive way to gain more cubic inches over a 350. It was a very good combination and won it's share of races. I later built a 400 using a stock 400 crank which I had balanced. I never thought it was that much better than the 372, but it did pull hard on the bottom end.
interesting--back in the 1970's some of the track engine builders were just stroking a forged 350 crank out to accept the early connecting rods smaller diameter, getting 360-370 cid depending on whether they went stock bore or .060 over. That was for the customers who thought the 400 had an overheating issue.
Yes, there were a lot of track engines built with an offset stroked 350 crank, but it wasn't as cheap as using a stock crank and a 400 block.
With methanol overheating wasn't much of an issue. I was told that I wouldn't be able to keep head gaskets on it, but I never had a problem. @@albertgaspar627
Going to listen and enjoy.
The 372 is like a destroked 400ci SBC.. Usually when people keep the stock bore on a 350 but put the 3.75 crank in, it comes out to 377ci..
You have shown me something I was wondering about. I was thinking about going to a 408 from my 360 La small block Mopar. I don't run much over 6000 RPM. But I need torque to move my 5789 lb. Van in the 1/8 mile. And I'm building it to run ether a procharger and nitrous or just a 500 shot of nitrous with a skat forge rotating kit with the better rods for it to be capable of 1500 HP.
Should have used the same camshaft. Lobe separation makes a big difference. So does cam lobe profiles.
Nice test show the benfits around each combo to build a car around a heavy street car id shoot for the low end tq and mutiply it with a set of gears and a good converter . a light chassis car im not worried about low end speed not that much mass to get going so the short stroke big bore is what i would choose.
But i wonder if you can get the best of both with a square motor? 4.00 bore 4.00 stroke.?
You can attribute about 14 fiddebees (ftlbs) of torque to the difference in displacement.... 383-372=11 inches difference. 11 inches * 1.3 ftlb/in = 14 ftlb....so that explains about 1/2 the difference between these combinations. The other half comes from variability in HCI. Displacement doesn't care if it comes from bore or stroke - so long as you're somewhere in the vicinity of "square" (ish)... Say between about 0.75 to 1.25 bore/stroke ratio.
Please do this back to back test with an LS + stroker, but use the same top end
Old Ford guys very familiar with long stroke larger displacement engines w/ poor airflow back in the '60s. Mucho torque on the low end. Great truck engines.
Look at things from the Crankshaft point of view. A destroke 372\3.48" is like a very good running 350. And it doesn't have to be a high revving motor. I've always felt one of these would make a great Street Blower Motor for a Weiand 144 or for a Turbo if you want the higher RPM's.
Lobe seperation angle on the camshaft
Yes the 110 should make more torque and at lower rpm
How about a stroker motor with a Roots blower? That's got to make some massive torque!
If you really want to see a great combo, build a 352. A 400, bored .030 for a 4.155 bore, with a 3.25 stroke and 6.25-inch rods. You can run 11.0:1 compression on 87 octane WITHOUT pre-detonation, and without retarding the cam.
On the Ford 302, First I would do is change the heads like a set AFR 195 or the bigger valved heads for Ford small Blocks. Yes a 351 Windsor would also be a great choice like building a a 408 for example. a fun engine to me would be building a 331 stroker bored 030 over and use a great set of heads, a great cam and maybe add a turbo to it. I would use a aftermarket block like a Dart shp block and appropriate bottom end parts and pistons to handle the high rpm it would it can rev to and put in something light like a 19631/2-1965 Falcon. it would be a lot of fun to drive!
Bill Elliott special... was beating 350sbc in Nascar using the 331 until Chevy cried foul!
Richard if you are going to do a comparison please use the same parts on both engines
Looked to me like the 383 wanted more cam. TQ peak and HP peak were so close together. It didn't rev out like the 372.
I always thought a stroker motor would make more low end torque than a large bore short stroke motor due to leverage. That why we use breaker bars on lug nuts instead of a ratchet. I know the difference in stroke is not much but it probably enough to make a difference.
All other things being equal, instead of a 4.125 bore 400 block *destroked* with a 350 3.484 stroke crank, or a 350 block *stroked* with a 3.75 stroke 400 crank, wouldn't a stock 4.125 bore 400 block with a stock 3.75 stroke 400 crank make more horsepower and torque than either of smaller displacement builds???? It seems to be common sense.
yes-bigger makes more
Longer stroke means less low range horsepower in exchange for low range Torque. The argument is that the 400 can afford to trade some torque for ponies.
@@neg4t1vezer04you can't "exchange low range power for low range torque. Power is calculated from torque and rpm, if one is lower, so is the other.
I guess it would matter on what you are putting the engine in and what you expect out of it. But one thing you performance builders miss now-a-days is that not everyone has to have an engine that spins up to 7k or has 500hp. A well built 383 for a truck that will run well on pump gas and still perform decently with fuel injection and still be smog legal and not cost 8 grand to build
Have you ever done a 383 build with a comp 270 magnum and stock vortec heads???? Or just the 270 cam swap into a stock vortec with a four barrel intake and a carburetor? It's nothing spectacular but it is something someone could assemble with off the shelf parts and no machine work?
I think the real benefit of a stroker vs a high rev configuration is that it can typically be done at less expense than the latter. Gears can be configured to translate to torque at the wheels, but for an engine to live in the high RPM's requires excellent balancing and a lot of high intensity parts. Not so much with a low rev torque monster.
Will gladly trade power at top, for street power in truck.
Different heads, different intake, and not the same compression. Not accurate comparison. But cubic inches is definitely a major contributor to the changes.
363 is a good ford combo. I like that big bore combined with some strong cylinder heads
Yes, way more power..
I'd also like to see a "stock" 331/performance 331 Ford.
I think the little difference in the LSA changes the Power band, maybe if had same combo numbers might had been closer . REMBER THE 112LSA Pushes Higher HP and lower torque, 110 lsa does the more torque n falls off at the top .
I think you can get away with more out of the 372 because it doesn’t experience valve shrouding like you would see with bigger heads on a 383. But built with smaller heads I think the 383 would shine because it has the cubic inch advantage
I like the 377 sbc the best!
Great report Richard. I went with the 400 small block with 350 crank & rods. The block is +.040, comes out to 380 CID. It has a mild cam with 110 LSA, full roller rockers in 1989 GM center bolt, aluminun heads. Using a performer intake with Edelbrock 750 carb. On the Dyno it did just what I wanted for a street car, 424 lb.ft of torque at 3400rpm. It really moves my 1980 Z-28 Camaro, 0-60 in just over 5 seconds. its been in the car since 1991 and still runs great. Next year I'm thinking of trying a better set heads. The factory heads don't seem to flow enough for top end HP.
David Reher of Reher Morrison convinced me that, all else equal, a bigger bore/shorter stroke is the winner. Less piston/bore friction, less windage losses, and better airflow through a given set of heads, you'll just make more power every time. He also explained why the longer stroke doesn't really make more torque than the same displacement increase from bore. Basically, peak cylinder pressure occurs not long after TDC on power stroke. By the time the crank rotates to where the rod throw is sticking way "out" from under the piston where the increased stroke really would have increased leverage against the crank, the cylinder pressure is mostly gone. So the highest cylinder pressure, and thus most downward force on the piston, occurs well before the rod/crank angle is enough to take much advantage of extra stroke.
I would add that what you might gain in leverage you'll lose in piston area, as well.
And in the end no one will race torque anyway, it's all about average hp. 😄
@@PSA78 Of course, average hp is average torque...
@@neilsmith8790 Torque is trapping efficiency of one combustion, hp is average trapping efficiency over a certain time (rpm). So within the same engine I guess you could compare average torque during development, though in the end it's always hp that will dictate things like acceleration and speed (and what's actually the best average for the application is dictated by gearbox etc; as in trapping efficiency measured at the wheels). 🙂
@@neilsmith8790exactly, HP= torque x rpm ÷ 5252.
(372 vs 383)
in this case it's a Dyno case. but on the track is a different thing.
the 383 cam drops-off the power some 530 RPM sooner than the 372 does. so at the track the 372 can take better advantage of lower gears than this 383 can. you sure do not want your 383 dropping off it's power 125ft before the finish line! these lower gears in the 372 will also make up for it's lower Torque.
to add, lets throw out brand. and you are building/making your own heads and block. the engine will be a 350 cid. what stroke will make more power with the 600 lift cam you have? a short 3.480 stroke 350 or a 3.750 long stroke 350? well, the short stroke 350 with it's 125" larger bore will have much larger valves.
The LSA was not good for the 372ci. It would not match the 383ci, but it should have been closer.
That being said, the longer stroke will always make better torque, while the larger bore will make horsepower per David Vizard.
off the shelf cams NORMALLY come with 110 LSA
herbert cams lets you pick the LSA whether or not you wan a cast gear and if its a small base circle or not
@@KingJT80 with "off the shelf" then yes, however as David Vizard says "never buy off the shelf, custom order your cams".
@@SteveSega Yeah he's the man not going to lie there but it's not like you won't make a lot of power with off yourself parts is obviously shown in the video you can do it if you wanted to
@@KingJT80 all the cam companies let you pick the lsa and lobe family
@@cedricwilson2055 yeah on a special order they will
Herbert cams literally has a drop-down menu on their website.
You don't have to talk to anyone to do it
Interesting!
Big stroke 383 for the win.
Torque for the long stroke quick horsepower buildup for the short stroke (higher rpm).
I prefer short stroke and big bore
I think it has more to do with lobe sep on the combos. Did the de stroke combo have lighter rotating mass? I've run both bore stroke combos on circle track and you can really tell the lighter rotating mass from the long stroke
Yes sir. I run dirt cars for almost 40 years. Gotta love the lighter pistons- always ran Ross ultralight in primary engine and whatever forged piston I could get on sale for spare engine. 6" rods in all, but again really good Manley in primary and cheaper but still decent scat in backup. Dyno never showed power gains. But you know we felt it off a corner. Acceleration rate was awesome with the liteweigh stuff.
A few years ago,i saw a interesting combo made,350 block ,4 inch stroke crank,5.85 rods,Ford Probe 347 style pistons ;-)
This is a camshaft thing. The RPM for peak torque and peak hp way down on the 383. Narrow lobe separation also points to lower rpm combo and quite frankly the comp cams is a peppy street/strip cam
Built 372 used dodge 340 318 rods didn't weld up crank , turn down the 350 crank 5 tho . For the pistons i used ford 273 312 rod bushings! Ran on alcohol, brodex 8s roller , dirt tracker cheap but great motor ran 4yrs. Never did a thing ,! Check at end tor apart bottom perfect, need rings won lots races, late model .it was a few years ago ! For got used 30, under or over as you say it ! Fit crank perfect !
It wouldve been more telling if the 350 block *WASNT* bored out and had the 4.0 bore making a 377 vs the destroked 400 or 372
I’d love to see that 347 with stock E7’s and a cam, then Gt40 irons, stock cam, then gt40’s and a cam. Thanks for all the info.
He has tests up of that already.
You got the motors there to swap heads to see if it's heads or bore or stroke
Big bore all the way for drag racing
The tighter LSA might have more effect than most people realize.
Try to find a Ford 260 and add a stroker crankshaft to get it close to 289 or 302 then compare to the closest one.
The interesting bit is if you gear the 372 to peak at the same MPH as the 383. Having the 372 shift when the 383 does at 6100rpm would net a 10% better gear ratio for the 372, which would multiply torque at the wheels - inflating the peak to 524lbs up from 477. It would end up faster than the 383 everywhere.
I get what you're thinking and it confused me too for a bit but this is accounted for in the HP calc (ultimate work). For an engine to make the same HP at higher RPM, it must necessarily be at a lower torque, thus the torque to the wheels is the same because the lower engine torque is multiplied slightly to stay in a lower gear longer. More gears, closer ratios and shorter gearing is huge for acceleration which gives higher RPM engines much better flexibility, but is theoretically countered by more gears in a low RPM engine.
I'm not doing a great job explaining this and I hope you're understanding the point. Older transmissions with 2-3 gears and long ratios made a huge difference in slowing acceleration, but a close 6+ speed transmission these days will make anything from a Diesel to LS to Coyote pretty close in acceleration for a given HP within a fairly wide acceleration range (0-120mph, etc). RPM limit becomes very important with few gears as optimizing for acceleration means a proportionate narrowing of speed range (basically drag rear end only, undriveable highway) relative to peak RPM.
I would think the long stroke small bore suffered shrouding of the valves. That reduced flow at high rpm
Thank you for the stock 302 vs 347, this information will apply to my truck build someday!
Don't go 347 tho if you're buying an aftermarket block, the 363ci is even better than the 347 in trq n hp..
you can't build a 363 from a stock 302 block
@@richardholdener1727 I agree.. I meant if he's buying an aftermarket block like the Dart..
@@P71ScrewHead I am sure you're right, but I only have sbc's, I was just talking in general principals of stroking an engine that will be mild otherwise, like my TBI truck.
@@harleysgarage327 Then the 347ci stroker can fit on the stock block.. Still 500hp will be the limit.. Very fun tho..
Big bore wins in my book every time.
Just look at the new corvette engine, and if that's not enough look at the Ford 427.
Great factory performance engines...
But I'm partial to them anyway...
For the 372 vs 383 there are too many variables to pin down where the difference comes from. Even with identical piston relief, head cc, gasket thickness and deck height the 383 will have about 1/2 a point more static compression. Then you get into dynamic compression being effected by the cam and even rod length. I think if you simply swapped the same H/C/I from one engine to the other, both with at least nearly the same static compression ratios, the results would be much closer.
And for the guys that say "long stroke=torque and short stroke=RPM" I ask what about the 403 Olds? It had a bigger bore than the Chevy 400(4.351 vs 4.125) and a shorter stroke than the Chevy 350(3.385 vs 3.48). When it was introduced in 1977 it made more peak torque(320lb-ft) than the previous year Chevy 400 out of an Impala(305lb-ft) at only 200 RPM higher.
The 403 was put in giant full frame sedans, station wagons and even GMC motorhomes by the way. Hardly applications suited for a "high RMP engine with no low end torque"...
I'd rather have the 372 in a lightweight car and the 383 in a heavy car or truck. The best thing about the 372 is that almost nobody has them. Seems like almost everybody and their brother are running 383's.
Probably half of those "383s" are really 305s.
383s are popular because 4.00" bore blocks are plentiful. Or were at least. The 372 (short stroke big bore) was a way to take a 400 block (plentiful in the 70s and early 80s) and use a factory steel crank from a 350 with spacer bearings, before offshore engine parts became so cheap. Thats were all this came from. Unless you have a rules limitation, or don't want to spend the money or an aftermarket block, you build what you have. Logically, 406 beats them both in most cases. I have a 383 in a daily driver and i love it. I sure wouldn't mind a 372/377 either. I would take a 406 over both.
Here is a test I would love to see. 421/427 SBC and SBF. Both use aftermarket blocks and rotating Assembles, Both should run 11.0:1 compression, Both use very similar camshaft design, both use AFR 225cc to 227cc CNC cylinder heads, both use Similar size intakes and the kicker? both use 950-1050 CFM carburetor. Here is the bore and stroke, 4.185" bore to 3.875" stroke. Let the war begin.
If you make them both the same, them both make the same
IF... If the heads flowed the same, the curves would be very similar. (The cost would probably be the biggest difference!)
Can you color code the dyno graphs when doing comparisons?
nope
Build the right 383. 4.185 bore 3.48 stroke
The 302 v 347 thing has been done before, Pontiac has been doing that from the factory since the V8 came out. You can put the same top end and cam in a 350, 400, 428, and 455 to see how much difference displacement makes. You can also see what happens when you increase airflow through the heads on those engines.
Only the 350 is small enough to move the torque band up with increased airflow. The 400, 428, and 455 all simply make more torque through the entire RPM range. Thats because the runners are the same length on every one of the, and that is where the torque comes from. The ports are kinda small for a 400 inch and larger engine, so the power band doesn't move much in the RPM range, it just gets bigger.
Pontiac is fun, because the main differences between the 400 and the 428 are main journal diameter and stroke, 3.75" vs 4" and the 400 vs 455 is .030" bore and a 4.21" stroke. You can get crank kits for the 400 block with 4, 4.21, 4.25, 4.35, and 4.5 inch strokes, that cost about the same as grinding a stock crank, adding forged rods, and new pistons. So why not make that 400 into a bigger engine?
The grunt from a 455 is addictive... especially with a 2.73 to 3.55 gear behind it. The 455 in my 65 GTO is pushing a 3.08 gear, and it pushes you into your seat far harder and longer than a car with a 4.56 gear does.... provided the tires don't go up in smoke. As long as you don't think more's better with gear like its a sbc, the Pontiac is an inexpensive way to the low 12s to high tens.
The problem is you aren't finding these engines in most junkyards, you have to find the entire car most of the time (usually 4 doors), and that is getting harder too.
If you weren't so far away Rich, I would bring stock and modified 400 and 455 engines for you to test. Might be fun finding out how much power my latest build with the tunnel ram makes. Its raining again today, otherwise some dragy runs would be happening. Maybe tomorrow morning, since its Sunday and the traffic will be lighter.. if its not moist.
let me know how it goes
Instead of a 400 block destroked with a 350 crank or a 350 stroked with a 400 crank, wouldn't a stock bore and stroke 400 sb make more horse power and torque than either???
Yep.
You know more than I ever will kon these matters but when watching the 302ci vs 347ci option i wonder what this would be like if you used better heads, intake and cam to take advantage of the 302? Run a 302 with a set of AFR 165s or TF 11rs, TF Track Heat intake then something like your comp XE274 or XE266. Then use all that on the 347, I’d love to see what the stroker does then. I did a 332ci back in the day and will never do that again, like you mention I’d either do a 351W or Dart 4.125” block if I want more cubic inches.
see the many other vids up on that
@@richardholdener1727 I looked but don’t see any comparing similar setups, ones that I’ve seen have different cams or intakes when comparing the different displacements have yet to see a dyno comparing same setup of 302 (head, cam,intake,exhaust) with just changing displacement….if it exists please reference where to find
So if you can benefit from increasing headflow from increasing bore and unshrouding the valves then thats the beat option. If the heads arent all that great then stroke increase would be more important?
beat opinion?
The big bore unshrouds the valves and flows better up top. Also wider LSA tends to carry up top. Stoker breathers deeper and has more leverage on crank to create more tq. 347 with small heads and cam gets benefits of longer stroke, but will only make so much hp because cam acts smaller on bigger motor and is flow limited.l so it cant make more hp up top.
The 383 maybe has a better power band for street applications but at the expense of longevity. The rod angle is atrocious, forcing the piston up against the outer surface of the cylinder bore. Not a good design.
My 377 big bore made 597 hp at 6400... with brodix trac 1 heads. A 669 lunati roller. 112lsa 500hp at 5k and still 500hp at 8k the point everyone misses we don't race dynos, the 372 will flat stomp the 383 on the track, example you'll be pulling 30 to 40 more points in the gear. That multiplies torque. We raced a 311 inch motor against 358 motors and pulled them 3 car lengths down the straits on a 1/2 mile track we were turning it over 8800rpm and we were mild on the gearing coulda turned the motor 9200 easy. People need to realize that. 99% of all Passing in done from the middle of the corner to the flag stand. That 30,40,50 points in gearing will do that.
Built 372 used dodge 340 318 rods didn't weld up crank , turn down the 350 crank 5 tho . For the pistons i used ford 273 312 rod bushings! Ran on alcohol, brodex 8s roller , dirt tracker cheap but great motor ran 4yrs. Never did a thing ,! Check at end tor apart bottom perfect, need rings won lots races, late model .it was a few years ago !
I like bigger bore most of the time.
By the way- Foot pounds of torque is for linear torque. Pound feet is for rotary torque- please use the correct designation- pound feet.
Will gladly trade power at top, for street power in truck.. On big bore vs stroker you have the 11 cubes difference..
Less stroke is better. More HP per ci and very revable! Piston ACCELERATION is the huge drain and increases hugely with a longer stroke at all rpm. Equates to better mpg too if it matters.
Increased displacement with longer stroke will make more total power but just not as good as big bore. IMHO
Makes sense but remember choice of pistons and rods can reduce the acceleration losses, as I did going .200 longer stroke with Ross Pistons and Crower rods which needed lighter crank balancing due to weight savings
I would love to see a comparison like this for a Chevy 305/334. Someone I knew years ago had a C10 that they stroked the 305 to a 334, as they wanted more towing power but didn't want a 350 (not sure why). Once they stroked the engine it really did have more low end grunt. I'd be curious to see a 305 stock/305 performance, then do a 334 stock/334 performance comparison.
that would be cool, since stroking a 5.0 Windsor Ford is common enough but it seems like few have heard about the stroker 334. then again, unless fuel economy is an issue, it's probably cheaper in the short run to nab a used Vortec 350 and swap the 305 for that.
I did a 302ci then stroked to 332ci is that close enough, the power curves were nearly identical with the 332ci TQ & HP curves moved up @ 40. I think the 332ci TQ curve peaked 500rpm earlier. I used 1 5/8” shorty headers for both and feel like they were holding back 332ci.
@@msk3905 was that a Chevy or a Ford? we were talking about both engines so I'm confused.
@@albertgaspar627 I know you are talking about Chevy but I’m talking about Ford
@@msk3905 that's why I asked, you said a "332" cid but most catalogs refer to it as a 331 stroker setup. interesting the extra 30 cid created nearly identical curves, perhaps it was getting choked somehow. I think this channel has videos before and after of Ford low deck stoker combos where the power difference is noticable.
to answer your question, yep, both engines are 4 inch bore, 3 inch stroke, for 301.9 cid. Ford didn't have the room for a 6 inch connecting rod that people think helps make power, but the Boss 302 used a longer connecting rod from the 289 engine, if you believe in "long rod" theory. Otherwise, the Windsor tended to use smaller head ports and valves to generate torque at a lower rpm, blowing away theory that a big bore short stroke engine must be a high rpm piece. it depends on the heads, as the Boss 302 pointed out.
Depends on the usage. 372 would be a better choice for racing and the 383 is better of a street car. A tighter lsa would be better for both engines.
if looks and the extra work were not a factor wouldn`t most be happier with a `modern` 5.3 or 6.0
Bang for the buck, most already have the old school sbc's in hand.@@hotdog9262
My question is. Which one is better for the 1/4 or 1/8 mile? High end horsepower or low end torque
Yes... Depends on the vehicle / chassis... a heavy vehicle needs the torque to accelerate for the quicker et while a very light vehicle could make better use of the top end horsepower for the faster trap speed.
Always maximize the displacement your engine block can hold…
I thought i was reading my own comment..lol i always say this..
This was interesting as most of Richards tests.
Dyno numbers are not always the same as what the engine does in a car.
dyno numbers indicate exactly what they do in the car
@@richardholdener1727 ? They don't indicate that they break stuff or perform right.
Example. I've got an old top oiler. Put a 428 crank in it. Stroker is the way to go. Right ? Now the car doesn't launch right and behave. Breaks parts. Broke the ladder bar twice.
I had a car that hooked up right before.
In my set up application, a dyno would show the engine making more torque, but not how it would behave in the car.
The rush of a short stroke is more reliable and exhilarating than the jerk of a stroker breaking parts.
Gm 637 CI BB 5.125 bore and 2.75 stroke
The drawback of this engine is only have three main
It makes you wonder why engine builders waited so long to utilize a big bore space engine when general motors already had one in the for years
Richard, when it comes to 383 vs 372 in the small block Chevy why choose? The correct answer is you bore out a 400 and make a 406! I would even trade a 383 to get a 400! I would never destroke a 400 on the grounds of "I want it to rev" on the street. In short, have your cake and eat it too!
Why do so many comments come across like ''i dont really know or understand but i want to sound like i know so I'll just parrot something from an Interguess Forum" 😂?
I recon if you cut/paste most of these guess comments into a google search you're going to find the forum/s they come from🤷♂️
Oh well., but again , great testing.
I always heard you get more head flow with a bigger bore because of valve shrouding
That's what everyone has been told and now everyone believes. But it may not always be true.
Some myth.
Use to be typically true. But designers have gotten much better with late model engines.
Like the match up. However, an accurate comparison should be same top end w same compression. Then cubic inch difference would be better displayed. I also know it's more work maybe? Unless you are pushing product advertising then I understand the various combos
pushing product advertising? you must be new
I now understand why Billy from SRC built his 372.