HOW MUCH POWER DID THE L78 375-HP 396 REALLY MAKE? WAS THE LITTLE BIG BLOCK UNDERATED OR OVERRATED?
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- Опубликовано: 8 июн 2023
- HOW MUCH POWER DID THE 375-HP 396 ACTUALLY MAKE? IS THE L78 396 A GOOD MOTOR? DID THE LITTLE BIG BLOCK LIKE TO REV? HOW MUCH TORQUE DID THE 396 BIG BLOCK MAKE? WAS THE 396 ACTUALLY A 402? WHAT YEARS DID THEY MAKE THE 375-HP 396? CHECK OUT PART 1 OF THE L78 375-HP 396 BBC BUILD AND DYNO TEST, AS I COVERED WHAT WENT WRONG WITH MY FIRST DYNO ATTEMPT. THE LIST INCLUDES SOME PARTS NOT SHOWING UP, SO NON-STOCK PARTS BEING USED IN THE NAME OF GETTING IT ON THE DYNO, AND THE BIG LEAK! PART 2 WILL COVERED THE STOCK MOTOR TEST.
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My hubby installed one in a 57 chevy convertble with a muncie 4 speed and 308 posi. Rear, we got married in 1970 and drove the 57 on our honeymoon ,
One of my favorite engines back in the day. Still is.
You aren't alone--Motion Performance made money selling customers' L78 engines to fund their L72 or L88 swaps. It was like the 350cid LS1 is now in the face of the LS3 or LS7.
very glad you will build it with stock components. no other way to see what it really made back in the day. wish someone would do the same with all of the musclecar engines and run em on the same dyno so everyone could finally know the real facts.
Yes Sir. The hp390fe was rated at 330 and the 428cj was rated at 335. That really don't add up🤔 Especially when a 68 b stock mustang held the record for years with a 428cj. I heard Bob Glidden dyno'd a 427fe rated at 425hp, and supposedly it made over 500 factory engine straight from Ford? I know a lot of the older big blocks was underrated. I heard the same thing about the 427 Chevrolet engine
Except for the non-stock comp cam....
Ditto!
The Comp Cam and the roller timing chain kind of ruined that didn't it?
Cannot wait to see how this turns out. Thank you!!!
Hey, congrats on 1/4 million subs, Richard! Great video! Loved the big block assembly stuff.
Glad you are spending time with Milo!
I built a 60 over 396 years ago. Filled block, 14-1 pistons, big roller cam , and extensive head work.
It out ran 468S .
Deja vu! Think part one got re uploaded good stuff anyhow! Have a good day Richard! Thanks for all you do!
excited to see dyno #'s vs. advertised. Everyone says 425 hp is realistic. I agree since these 396s love to rev and GM seemed to give numbers at 5,200 rpm.
that is a gross reading with no muffler, belts, or air cleaner. With those items attached the NET horsepower is about 350.........
@@chadhaire1711 This is not a difference in Gross vs SAE net HP rating. Saying the marketed 375 hp gross may actually be 425 hp gross. Agree it will make less with accessories and at tire.
@@BBBILLY86 There is a big difference in gross vs net...I dont think you even know what it means
@@chadhaire1711 I said there is a difference between Gross, Net and Tire numbers. I clearly know the difference. To clear it up for those with low reading comprehension skills. My original statement and Richards thought is the Factory rated 375 hp may be 425 hp in reality. Now stop trying to act like you are some genius by acting like this is all due to Net vs Gross ratings. The theory is AGAIN the factory underrated this motor. Does that make sense?
@@BBBILLY86 The car makers never under rated engines...it was a myth so sell more cars. GROSS means NOTHING. Net means everything.
This motor is 350 hp net at best......any modern V-8 does better.....so take your superior reading skills you claim to have and..........
Looking forward to seeing the results. Stuff happens.
Stock exhaust guides are tapered about .oo2, make sure you have a good machinist. I have actually overbored the guides in the past and pressed nontapered cast guides in. I also coat the inside of the bore of the guides with Teflon thread seal, it helps stop the leaks.
I was all excited to hear a big block run and at the end I almost cried😢
Guy gave me a ride in a new '65 or '66 Chevelle with this motor in it. Fastest thing I'd ever been in until I supercharged my '05 CTS-V in '07. That 396 was incredible.
I rebuilt a crate 1970 L78 in my 66 Chevelle SS396 (not original to the car), 4 speed, 4.10 rear and left it stock. That includes exhaust manifolds and points. Only did slight bowl work to remove some rough casting. Never dynoed car but it ran a best of 13.86@104 on BFG T/A's.
My 66 Chevelle Malibu has a 1971 small block LT1 350 making 375hp with 11 inch clutch and 4 speed trans
My 66 Chevelle SS has a built small block 327 and is in the 600hp range , Forged Steel Vette Crank in a 4 bolt main block , 12:1 Forged pistons, it has an 11 inch clutch , Lakewood Blow Proof bell housing, M-21 Muncie 4 speed and posi rear end , pulls both front tires off the ground and revs to the moon at 11,000rpm before the valves start to float ,
My 3rd 66 Chevelle SS has a built small block 327 and 4 speed trans with a posi rear
I like the 66 Chevelle and can tell you where and when every single 66 Chevelle was made on the Assembly Line
There is a letter in the V.I.N. after
13817 and this tells what Assembly Plant it was built and the Cowl tag under the hood right beside the windshield wiper motor tells what month , the original paint color, bench seat or buckets , and color of interior .
That is about what a 5.7 Charger runs but carrying 600 more pounds
@@jtc1964x,
66 Chevelle weight is 3200lbs with a small block
66 Chevelle with a big block , add another 200 pounds to that
@@jtc1964x My 2004 GTO ran .5 sec quicker and that weighed 3800# stock. Its amazing what 50 yrs of technology can do.
@@jerryzotta4482 What is so amazing?
Richard I would love to see you run this engine with a set of AFR 265s and a RPM AirGap or something similar. Some of us nostalgia guys love our small cube 396's and 427's but really would like to see what a set of modern cylinder heads and an intake would do. If you are putting your Chevelle together and just want a bit more pep is that the best way to get it and stick with a short stroke small cubes big block???
We wonder...
I HAVE AN AFR OVAL VS REC PORT HEAD VIDEO TEST UP-THEY WILL BE BETTER. BUT WHAT ABOUT THE COST?
Nostalgia too the MAX! A bit emotional with this one. Can’t wait for the next installment.
I had almost the same set up, but I had the 96 (could have been 98) CC chamber large valves heads, I don't remember what the compression was, but it was a lot and an Isky mega292... What a screamer, hold hard to just under 7500.
1965 Corvette 396 was rated at 425 hp.
From 1966 thru 1970, the 396 was rated at 375 hp. Since the motors were identical, Chevy always claimed that the difference was from the superior breathing of the Corvette's exhaust system. (50 hp is doubtful) Running on the dyno with headers should easily show the 425 hp. I'm interested to see what the stock manifolds will do.
Were they rated at the same rpm?
That's always a cute trick.
@@MrTheHillfolk 6400 vs 5600
@@rondpert5167 aha ,thank you sir!
I coulda seen it on Google but it sounded like ya knew already.
I think ford low balled all those cobra jets and the hot stuff , I coulda swore I saw a vid where one of those was rated at 3600 🤣
No wonder it had 350-360 advertised HP 😁
(What we car guys wanted to know ks what's she do at 5k 😁)
In 1965 Chevy also offered a different (L37) 375-hp 396 in the Corvette
425 GROSS on the dyno is only 350 NET in the car......big deal......a 2023 Camaro with 3,6 V-6 is 335 NET.......almost as much.
Looking Forward to this one
Always wired the pick up tube to the pump. Seen a couple fall in the pan over the years.
My grandfather and great uncle were banger and flat head old school guys. So I have always liked model-a and pre y block. What really opened me up was one of my dads friends had a 69 vette 4-spd late 90s high hp 400 sbc and a 66 chevelle with a 396. I sure do love some vermin!
Believe it or not i had a stock 292 y block with a 5 speed that would stomp on 350s. It was just tuned perfecto. I love love love the sbc and I know what they can do so it always surprised me that my little 292 would hurt egos. Honestly those sbc had to be over carbed, and out of time.
I'm building a 6 deuce 312 for a future build.
i have seen that on BBC heads before on friends marine applications. looking forward to the results! as a 67 Fairlane owner, the 390 unfortunatelly didn't have enough for the 375hp chevy, or even the higher end 389 Pontiacs. Ford had the parts but the Mustang took all the glory.
love the dyno testing, keep at it!
Ford's 390, IMHO, is a very underrated engine and I'm a Chevy dude. Not as diehard as most but it's hard to argue against the 350 SBC.
The 68 1/2 428CJ was the answer to the 375hp 396 and still, they were close.
@@mcjams66 it's crazy how underrated most of the BBs from the '60-early '70's engines were. Not to mention how easy it was to increase power without even opening it up.
It was rated by chevy 425 hp. In the only year it was installed in a corvette, most people dont know that! Reasearch it , its true , it had a solid lifter cam and hardened rockers, and would rev to 7,500 rpm. We had one in a 57 converible! My hubby purchased it from Burger Chevrolet in 1970.
425 gross horsepower with muffler, belts, and air filter removed. With all those items installed back on to be street legal the NET horsepower was more like 350......car makers stopped using these fake gross numbers in 1972.
I'm surprised no one was complaining about the block wasn't taped of when it was painted lol 🤐
You chase the threads, you don’t tap them.
@@Cultofpersonality09129 I believe the proper spelling is tapped. Uncle squirrel spelled and spoke correctly. He meant tape, as in painters tape.
My thoughts too is there over spray paint every were
It’s Richard. You know that engine is gona run mint either way. I used to be so meticulous with my engines. Then you build a couple hundred and you see other engines people butchered and they still ran and some of those details you were Adam it about years ago just don’t matter on some pieces anymore.
Damn auto correct. You know what I mean. Lol
Did not read all of the comments or if you were aware the old style guides drive out towards the spring seat .. the new style drive out towards the combustion chamber .... I dig Gen 1 BBCs ...
I have a lot of respect for that engine and the BBC in general but waiting for you to do same test on a Ford 429SCJ.
Love this channel.
wish I had one of those
I used to put that crank in a 454 block and use trw L 2300 pistons the rods out of the 366 or 427 tall deck. A worked pair of ovel port closed chamber heads and terrorize the neighborhood. Good times
DIY 427?
@@deoderantguy1 yessir
Nice
Richard my friend, I hate to say it because you do good work but without a Factory Spec L78 camshaft you really don't have an L78 engine. The camshaft is what makes the personality and powerband of an engine. Needs to be identical. A True L78 cam is the same as the LS6 cam BTW. The cam you have looks to have more lift and be a bit bigger.
we planned to run the stock L78 cam-this cam was NOT represented as a stock cam-it was only what we had at the time of assembly to make the dyno
You obviously didn't pay attention to the video!
I cannot wait to see what this thing does.
Great to see somebody took time to deflash lifter valley
Hi Richard, how is it going with this build? Thanks
Never drive out stock BBC guides, this happens ! Core drill and ream them for sbc 3 eights guides, they were available for 400 sbc truck exhust, some were factory 3 eights stem with 1.6 exhaust valve !
HELLA COOL STUFF
Hey Richard, when? Please!
Can't wait!
First off , the L78 was a 375 Hp with aluminum head option. Cast heads made more Hp, the aluminum heads needed the exhaust short side radius. Opened up.
Tge 66-67 used grooved rear cam bearing with solid no groove cam bearing. 68 up different. This guy spends too much time looking at synod sheets. Back in the day a goidxrunningcL78 could walk all over a Hemi, same as any warmed over Z/28
the L78 was NOT an alum head motor-only when combined with the L89 head option.
So, Richard, where is the dyno tests?? Very curious as to the numbers.🤷♂️😄
To bad but i know 396 will be back on dyno soon enough.
Thanks for everything always love watching ur stuff
Thanks u.
Pulled out my aluminum head 468 out of my 68 Convt. Camaro and put a original 375/396 in and I’m surprised how low power it felt compared. Great engine though!
im wondering what were/are the cam specs? duration @ .050 is a good indicator of the usable/effective rpm range.
Appreciate you doing this combo. Once you get it figured out I've always been curious how the power curve would change with a set of Oval Ports having a smaller runner and a better port velocity. Do you think the Ovals could give the Rectangles a run their money or even possibly out perform them ?
I'd like to see that too. I have some big block large ovals closed chamber heads 049 i think.
I had the 2.19 1.88 valves put in my closed chamber oval Port 396 head's on my 68 Camaro seems to work great still puts a smile on my face when I open the 4 barrels
Richard, do you have access to the GM factory Low rise Rectangle port intake that came in the Nova/Chevelle? I have one and would be interested to see if any perfomance was to be made over the High Rise or was it purely for hood clearance ??
You will be fine with nice oval port heads as long as you aren't looking for every last horsepower in a race situation.
I get all tingly look at a Big Block Chevy with the valve cover off!
No dyno test, such a tease!
When is the follow-up to this planned? Seems this video came out a couple of months ago.
Good stuff. Thanks for the great videos.
Richard, are those roller tip rockers worth any noticeable power over stock stamped rockers??
not sure
@@richardholdener1727 Maybe do a dyno test sometime??
If i remember correctly David Freiburger had a test on them way back when he was on RUclips
@@BuzzLOLOL LOL...
Seen this before! How's it a new video?
removed and reposted
So I picked up a Gen 5 block and heads for $40 and then Gen 6 intake with injectors, cam, crank, rods, pistons and more goodies for $75 bucks and I'm wondering if I should put all that in the Gen 5 block, and use the hydraulic flat tappet setup I have, or use the roller cam and some LS roller lifters I have with retainers, but I think it'll blow itself up haha
Ok, so, where is the new vid? I’m really interested in this one since I have a 1970 L78 in my shop. I’ve had it for over 20 years by the way. 🤣
Coming soon!
@@richardholdener1727 sweet!!
@@richardholdener1727 Or not.
The '67 L-78 Camaro, and '69 L-78 Nova came from the factory with a 780 CFM mechanical secondary (not vacuum) Holley dual-feed, dual squirter carb, with separately installable metering jets for each barrel. On the '67 L-78 Camaro, there were two different part numbers for the carburetor depending on whether the car was built in Van Nuys, California (LOS on trim tag), or Norwood, Ohio. There were only around 130-140 '67 L-78 Camaros built at Van Nuys, The reason for the different carburetor was that the Van Nuys-built Camaros had a smog system called "AIR" (Air Injection Reactor) that used a pulley-driven pump to push metered amounts of filtered air into the exhaust manifold close to the exhaust port to help burn any un-burned exhaust gas. This required a carburetor with a slightly different calibration in order for the car to run "right" (albeit with smog junk). Most of the '67 Van Nuys-built Camaros with L-78's had the smog stuff ripped off of them and tossed, and a good set of headers put on, as well as swapping the carburetor for one of the carbs put on the Norwood cars. The 'smog' version of the carburetor apparently just wouldn't run right no matter how hard one tried. Popping the Norwood part number carburetor on the engine immediately fixed the issues. The Norwood-built cars did not have smog systems, and around 1,000 of the '67 Camaros with L-78's in them were built there, with the official production total being 1,138. By '69, all production Camaros and Nova (as well as Chevelles and "big cars" had the AIR system on 396's and 427's. The exhaust manifold for the passenger side of the engine on Van Nuys-built L-78 Camaros is unique to only these few cars, as there were some modifications needed in order for the AIR injectors to clear other aspects of engine components. The passenger side valve cover on the Van Nuys '67 Camaro was also unique, as it had an extra bracket spot-welded to it that was a support for the AIR hoses. Both the original exhaust manifold and valve cover are very rare - it's almost impossible to find originals (though they are reproduced). The driver's side exhaust manifold for Van Nuys built L-78's was the same as the Norwood version, except it was drilled and tapped for the AIR injectors. While it may be obvious to you, I figured I'm mention that putting "generic" big block exhaust manifolds on your engine may result in a performance issue. They must be exhaust manifolds made for the rectangular port heads, as the exhaust ports are considerably larger on these heads, and using "oval port" exhaust manifolds on rectangular port heads will result in a port size mismatch that will rob power. You could use any set of high-performance 427 (e.g., L-72) solid lifter engine exhaust manifolds in order to "match" the L-78 exhaust manifolds, assuming no smog system would be used on your engine. Fitment will vary depending on the vehicle the engine is going to go into, though.
The l78 camaro in 67 has a vaccume secondary, ask me how I know? I have an l78 67 with 22000 original miles on it sitting in my garage that my dad has owned for the past 52 years and its got a vaccume secondary on it
Curious since the smog/air pump only injected air into the exhaust manifold to help burn off unspent fuel what performance issues would there be using one or not? I understand the smog pump belt would eat up some HP but are you suggesting injecting some air in the exhaust manifold could cause performance issues? Thx
@@domsgarageYou are correct, Dom, not that you needed me to tell you. Like you said, it's right in front of your face. The 780 is a vacuum secondary. Want to know how I know? Because my '67 Z28 has one. Also, only the cars built in California that were TO BE SOLD in California came with emissions in '67.
Can't wait to see what it really does
Wouldn't it be easier to install the cam before the crank to facilitate guiding it in thru the bearings?
crank and rods first
Damn... gotta be frustrating!
One quick thing to think about when building an engine...who's torques specs? What should you follow the manufacture of the engine, or those supplying the bolts. Is there a protocall where you should follow one or the other, or not exceed one or the other? A prime example would be using fasteners way out of range from factory specs. Say at what point does the engine fastener need for proper stretch, before you start distorting the factory casting..... rod, main cap, cylinder head,ect.
THE MANUFACTURER OF THE FASTENER (LIKE ARP) PROVIDES THE TORQUE SPEC
they said the 366 truck engine had the L 78 crank in it and my friend heard from the machine shop once that older farm equipment with gas engines in it had HP stamped blocks but the engine just had a smaller cam and a two barrel carb on it
I would have used etching primer to the block before painting.
Richard when will the final test be?
Any updates on this L78?
My factory 65 Corvette produced 226 at the rear wheels.
They have a turbojet 396 in a gm museum says it debuted in 1965 had 2 versions a 325hp and 425hp
they also offered a 375-hp version of the 396 (L37) in 1965 in the Vette
I believe this engine was NHRA rated at 425 HP.
Was it rebuilt to stock.
Legend, ,,, !
Why was this repeated? I enjoyed watching it, but was hoping for the update on the heads and a new test.
had to remove vid and repost it
We had a 1971 402 with a 650 Rochester in a 1979 3/4 ton crew cab long box. Pulled 31 foot 5th wheel from Northern Alberta to Seattle every summer...12 mpg loaded or empty didn't matter 😂
My 81 GMC c3500 is tuned to perfection and the best cruising MPG I can get is 11. TH400 and 4.56:1 are never going to produce modern car MPG. 😭
Right on
I want one of Richard's "wrong cam" t-shirts!
Is part 2 of this available ?
not yet-soon
Leaving aside that gross net and bhp are not all the same...A thing most 'car guys' and fans of the muscle car era forget or are not aware of this how uncommon it was to find a dyno in the late 1960s, and that not all dynos produced the same results. There were "good" dynos and "bad" dynos. The manner in which the car companies published the ratings also were not all the same. Some manufactures used the best ratings from a selection of engines. Some published ratings that the engines reliably and repeatedly made across a selection.
Richard, I wish you would have followed through on this project. I have two stock L78s sitting in my garage and was wondering just how much HP and torque they make.
coming
If that engine doesn't make 425 H.P., start checking things over because something is wrong. I used to work on my friends 69 Nova L=78 with posi rear and Muncie, with headers and an aluminum flywheel. It would definitely plant you firmly in the drivers seat. We took it to Cecil County and first time out we were in the low 12s. It ran better after getting it home and doing a thorough tune up. That engine today can be even more awesome without adding any power adders. Good luck with the rebuild. Dams shame about the guides. Hope you find what is the cause of the guides passing water and I hope the heads are not cracked from whomever drove the guides in place.
425 on the dyno is only 350 net in the car....big deal..a 2023 Chevy V-6 puts out 335 net.....
OK, so what do you have that you personally put together and had on a dyno? Curious because you are a naysayer. If you don't like the video, don't watch it so you can make diminishing comment.@@chadhaire1711
@@4speed3pedals I dont have to put together an engine Goober.....I can put together facts about GROSS horsepower vs NET, which you obviously do not understand. Your imaginary 425 horsepower number is a GROSS DYNO figure, with no muffler, no belts, no air cleaner, no smog gear.........just bare engine. Put the muffler, air cleaner and belts back on to be street legal and you just lost at least 18% at the crank......down to 350 NET horsepower. AS of 1972 ALL engines sold by manufacturers have to be rated NET not the old fake over rated GROSS system. So a factory 1970 396/375 hp is really only 305 net hp. That is less than a 2023 Chevy V-6 at 335 NET horsepower. That 1969 Nova had a lot more mods than headers and flywheel to run anywhere nears the 12's....LOL......YOU are the naysayer Goob.
I heard using Buick valve guides will stop the leaking.
Hey Richard, I was wondering when you are expecting to complete the repair and post the dyno results video? I can't wait, buddy!
after it is ready
@@richardholdener1727 ha ha
Is the major delay in putting this back together waiting on the Elgin factory spec cam to be delivered? Also, is that a common issue with valve guides (exhaust) perfing the water jackets?
Elgin cam is already there
I've never had a bbc do that.have had prob 20 or more.
Old school hotrodder here, back in the day we cut the guides and rewelded
I’d love to see the Oldsmobile 455
That depends on what one you build, the 1965 6 month motor or the rest 1966 and up..
I wonder if they drove out the original guides? If I'm not mistaken, we used to bore out the old one and install a guide inside it bc of that and the pia it is doing the VJ after removing the original guide from the head. Removing the original ones will give you water issues too. That sucks that happened I was wanted to see the numbers.. Im about to build one
we have it fixed now with new heads
@@richardholdener1727 love to see the difference between the factory hp heads and the new ones
How's this coming along? What hapened with the water leak?
fixed
MY GOOD FRIEND HAD A BRAND NEW 1967 396-375. THE SECOND DAY WE DYNO'D IT AS IT CAME FROM THE FACTORY. PULLED 412 HORSEPOWER. THE GOOD OL' DAYS
Pro tip: Try canned air to unstick the CapsLk key.
412 dyno is only 330 hp net
@@chadhaire1711 THANX 4 THE NOTE
im sure its already been said but the machine shop is supposed to pressure test the heads.
no stock 396 numbers?
Please try a set of peanut port heads.
Did we ever get any final numbers??
not yet
had one in a 69 Chevelle. I would love to hear it idle, one more time.
Ok the 425 hp 396 actually had aluminum heads and I may be wrong about this but I think it was only available in the Corvette with the aluminum heads
the l78 didn't have alum heads, but the l89 alum head option was available for the l78 and l72
The L78/L89 option with aluminum heads(which put the L78 on a diet weight-wise, but weren't quite as good as stock iron heads) was available in '68 through '70 on any Chevrolet vehicle that you could get the L78 in, which included Camaro, Corvette, Nova, and Chevelle. The aluminum heads were not available on the '65 L78 Corvette, nor were they available on the '66/'67 Chevelle, '65 Z-16 Chevelle, and '67 Camaro. Novas got the L78 in 1968, and thus could get the L78/L89 option right out of the gate.
Big blocks prone to hanging up valves. Need bronze guides
Which one is the power/torque king is it a 383 sbc or the 396bbc...Can't wait to see it running!
Theoretically the bigger engine will always win
I love love love SBC but I think the 396 wins this one.
The Aftermarket has blown away what we were limited to in the past. The 383 became legendary because it used factory parts. You can actually buy a 385 Crate Engine from GM.
If I could (afford) build what I want, it would be either a mid-80's Bonneville or Malibu Wagon with a 427 Aftermarket SBC with a 5spd. and probably either a CPP Pro kit or Hotchkis suspension for hauling the family around. More than enough power to get in trouble but still reliable enough to be a Daily. Because it wouldn't be "Built to nines".
if the intake ports are too big....torque will suffer at lower rpm making looser converters and/or higher numerical gear ratios necessary for good acceleration. more cubic inches will tolerate larger ports to some extent. of coarse bigger ports allow more rpm and hp up higher. its a trade off similar to camshaft and intake choices. @@loganamurray64
i have a 68 l78 396 still factory never been apart still has under 100.000 miles but it is no match to my ho 450 hp 454 got 4 setups for free from 6,000 to 58,000 miles on them plus they came with the 02XX 400 r turbo good to 800 hp comes with heavy clutches heavy 8 bolt pump stage one shift kit from factory u can have a good engine but with out a good trans u don't have shit the 02XX trans is the best u can get from GM factory setups
I like the big block chevy for power, but the weight is to heavy.
@Bill Jr yes, underrating the hp was a way to avoid the S*h*y*l*o*c*k*s in the Insurance indusry.
The laughably-low "415 hp" of the L88 Corvettes comes to mind.
l88 was rated at 430 hp
Chevy only built a small number of L88's and they weren't advertised. They only wanted them to be sold to pro racers since it wasn't built as a street engine. I think they were rated 430 hp around 5000 rpm but would rev much higher and peak hp was much higher. I have read a few reports of people rebuilding accurate replicas and seeing close to 550 hp on dynos. They were also really expensive!
Car companies never under rated their motors to feel insurance companies.....myth....they over rated by using fake gross dyno numbers..MOPAR 440-6 was advertised at 390 hp but was only 325. 396 375 hp was really only 305 hp
Bracket car, 2200lbs dry....vacuum secondaries were 2 tenths quicker at 60 ft. versus WOT......there ya go!
Port velocity.....I'll say it again....ahem, PORT VELOCITY!!
so you think you were running to the 60 foot on the primary circuit in a race car?
I know a guy who dyno'd an LS5 and said it made 500 hp.
stock?
@@richardholdener1727 so i was told. Im sitting here wondering if it was the ls6 instead. This was a conversation i had back around 28 or so years ago lol. He wasn't a bs'er so i had no reason to doubt him.
When is the next test? I can’t find the next video.
not run yet
Guess we aren't going to hear about the leaking guides? The head shop F up? You don't want to say? LOL
The leaking guides were the highlight of the video-they have been fixed-not sure what your point is
The cam you want is Comp.11-106-3 .The oem replacement .TRW made a piston to make that block a 427.
the comp cam is not a replacement-it was not done on the factory master
Didn't you post this video already?
Noticed on the Pistons they were 30 over so what you have now is a 402, it is not a stock 396.
IN 1970 THE L78 396 WAS A 402
@@richardholdener1727 who do you think you're talking to some Millennial that don't know any better, I have been a Doer not a reader, I was rebuilding a lot of those engines back in the late sixties and seventies still doing it today. They were not all 402 a lot of them actually were 396, matter of fact I have a block and pistons and rods and crank sitting on the floor of my shop right now. Some of the 70 Chevelle have 402 Fender badges on them, a 402 was a screw-up when somebody overboard the 396 so they sold them as 402.
Best laid plans of mice and rats.
Those rat motor guides were not precision, so when you replace the guide the seat has to be pulled, or put in a seat. Which isn't horrible with unleaded gas. It just srarts getting farther from "original:". Also, those old motors responded to a decent 3 angle valve job, but finding a set of fresh, stock heads is pretty unlikely.
For purity, would be good to match factory total timing. Then see how much it responds to optimal timing.
LMAO!!!!!
Factory cam specs for comparison?
that is going in