There's no question the new engine tech. is much better but that's another video it's amazing when you talk about a certain engines IE: BBC how many people jump on the comment section and feel the need to convince everyone that anything that is old is a waste of time. Yes the new engines of today do make more power for their size. and the engine management system is much better, however this video is about the iron BBC heads, never ounce did I say these heads are better than new technology so please CALM DOWN! if you want to compare new tech to old ummm make a video of your own
My point is that most of the good thicker castings are gone. They are a rarity now. Your video video's are rehashing material from a Petersen Publishing HP book from 30 years ago. Although you are verbally describing the BB Chevy heads characteristics, You are reiterating David Vizard and the other authors stuff.. They are experts. Those authors did your research and made the effort. You are appearing to be BB Chevy god to a younger "lack of knowledge" crowd. Maybe those HP authors should be flattered at your imitation. Or sue....... To the younger guys, my advice......Buy a set of aftermarket new iron heads for the early Mark IV BB Chevy. Or cough up extra $$$ for aluminum street heads. They are not worn out, and possibly angle milled and thin, and you will be $$$ ahead. 90% of Chevrolet castings after 1976 are thin wall castings for low compression and have poor resistance to cracking at exhaust seat area, Panic-mode now by wholesale warehouses loaded down with shelves of old school parts. To make old school work you will spend four thousand dollars for electronic throttle body injector by Edelbrock, Holley + MSD otherwise you will be continually fighting detonation with the old school stuff. No variable valve timing and no detonation sensors in the block. No automatic fuel re-calibration by the ecu for stupid blends of 15% ethanol approved by Obummer. Town to town travel in old iron block is questionable unless you enjoy filling part of trunk with octane booster. A Ford, Chevy, or Dodge V-8 made in the 21st century can live with 9 psi boost on 92 octane pump gas and not have it's owner screwing with timing curve every time he hears rattle in the block at fill up time. I am 50+ years old, and prefer driving instead of buying/installing short blocks that can't live on modern fuel. And the new blocks/heads get 40% better mileage with higher power and lower weight. All the SEMA guys make the good stuff for the modern stuff too. Old block/heads = Ragged edge of destruction. Good at oiling down main-street. .
What those people also dont understand is MONEY. Yeah, the lastest and greatest does make more power, at the same time its alot more expensive. Even nowadays and older setup can make modern horsepower figures often for alot less cash.
Bone Daddy The new LS1 Chevy is the most popular swap engine today. The new small block. I have a new December 2014 issue of Mopar Action and it's also got another hot trend-Disc brake conversions for older cars. The old sheet metal styling of 60's- 70's era cars is cool but most need new quarter panels, or floor pans welded in after 40 years of rust. It's easy to dump 15-20K into an old car. Someone recently did a Dyno test of the $80,000? Hellcat Challenger SRT. It was laying down HP numbers over 722, not the factory advertised 707 HP. Eight speed auto with A/C, Sat/Nav, WiFi, plus room for four. The Hellcat uses a Layton type supercharger. The nice thing about modern muscle[Camaro,Mustang] is that it's now everywhere instead of only at swap meets and now a rarity. I can get parts at a dealer. Buy a road racer like the Shelby or new Camaro. The 2016 Ford H.O. V8 is gonna have a 180 degree flat crank like a NASCAR V8. The new Camaro SS is starting to turn corners like a Porsche. Don't stay in the past: It's like bringing a flintlock to a machine gun war.
My first bbc .30 over 454 had oval port, closed chamber big valve heads it made enormous amounts of torque, also done extensive port matching, it ran very well. Great video!
I had just built a peanut port head build, has a very mild hydraulic cam, 10.5:1 comp with a torker 2 intake, 2 inch spacer and demon 850 carb That motor in a full interior 78 z28 with a cage and 4.11 gears ran 12.9 at 104 mph, really impressive motor
Thank you for the very informative vid. I'm not a BBC guy but currently dealing with a boat motor rebuild with a Gen 4 454 and heard about the Rec/Oval ports and didn't know much about it. Now I have a better idea of what's going on. Thanks Again!
BBC is way cheaper to get into compared to LS, BBC doesn't care if it runs fuel injected or carbed, LS is built in such a way that expensive aftermarket intake manifolds are necessary in order to just install a carburetor. a lot more BBC stock available too, LS just isn't cheap enough for an intermediate enthusiast to start building. Also for towing purposes and good traction in the snow, the extra weight in a pickup truck from the cast iron BBC is going to help keep the front end tires pressed down, the LS is going to be too light to haul heavy loads, and won't have near the stroke torque these things can output.
Midnight Mechanic the manifold to carb a ls1 is expensive because it has to flow a lot you can get cheap manifold but they don't flow that's why ls1 is so popular because 350 hp 350 tq stock a lot of big blocks make torque but hp lacks 430 tq 190 hp runs out really quick
@@utahcountypicazospage5412 they never made a big block with 190 lowest at there worst was 230 and a cam change headers intake and good ignition puts them up to 400hp.
For oval ports the 781 and 049 castings are the best iron oval ports that Chevy came out with. With big valves and a mild port job they actually perform quite well.
@@douglasadams6024 your comment makes no sense. Car Craft did an engine build with TRW flat tops in a .030 over 454 with 781 heads and a flat tappet hydraulic cam and the combo put out 425hp and over 500 ft/lbs of torque. I have basically the same engine and in my Impala it ripped for a heavy car and 8 to 1 compression. It all depends on what you are trying to achieve.
You are exactly right about 427’s and oval port heads. I have a 427 in my 1966 Chevelle and I surprised an LS6 Chevelle and beat him easily. He sold his 1970 stock SS after that which was a shame. He said “I have rectangular port heads so I should have at least 100 more horsepower than you do!” Wrong! That was in 1983. I still have it and it runs great. I saw him at a grocery store a few months ago and reminded him about it but he said he didn’t remember the race!
A couple of corrections: The 496/8.1 was sold new up to 2010 as a motorhome engine for the Workhorse chassis. It should also be noted that the 496 is a LOW RPM motor. Red line is 4800 rpm, and you do not want to exceed that. Its a great low rpm motor, but not good to scream it for HP. The crate 502 is much better for that. Second thing to point out about heads. Fast burn heads are tons more efficient. The combustion chamber is much tighter around the plug area. The most efficient time to push on the piston is at 14 degrees ATDC. Energy occurring before that time or after that time is less efficient. Fast burn means the pressure build up occurs within a narrower window, so that more energy is closely timed to occur at 14 degrees after TDC. Not only does this improve efficiency, but in addition, the faster burn reduces the likelihood of detonation. As a result, higher compression ratios can be used on pump gas. 9.1 on 87 octane. 11.7 on 93 octane.
I have a set of 049 Heads with bigger valves huge port job, 11 to 1 in a 454 .060 over making 632 on the dyno. Running 114 race gas. These heads are so nice. I'm running a Clay Smith solid lifter cam nice power and tons of torque. I really liked your video a lot, very informational, Thanks.
Nice video. I have been running BBCs since 1970, when I swapped a 1967, 350 HP Chevelle 396 into a 55 Chev Cameo. The reason I brought this up, is that my heads have the D port, which is D shaped large oval port. I can't remember, but I thought it was a 208 casting. This was a weird engine, in that it has the factory high rise Holley manifold and carb. It is a fantastic street engine. I also have a 68 427 and 2 454 engines. I mention this because, my 435 HP 427 has a heavier piston than the 396 and the 454, which means that it also has a much larger, 8 inch, front balancer. The other thing that you might mention, is that the heads had three, maybe more, different chamber designs, the closed chamber, the partially open chamber, and the full open chamber. I thought this might be important t mention, because the pop up pistons for these different chambers are not a universal fit and caution is advised when mixing and matching heads and pistons. Another thing, I thought was important, was that the 396 and 427 are internally balanced engines, and the 454 is an externally balanced engine. I know you couldn't mention everything in one video, and I did enjoy it. I love these
I love that you touched on the 402 BBC. In my 1947 Ford truck sits a 1972 402 big block Mark IV LS3. Not going to win many races but it was my father's daily driver. This motor, transmission and carburetor all came right out of the same vehicle together and that's how they will stay. Good stuff :)
Love those peanut ports! I have had lots of big block street cars and the 236 heads are by far the best heads for torqe and throttle response! My budget 454 just went 11.60s with 236 peanut ports.
Those heads are not peanut ports. Lot of misconception about the bbc heads. There are 3 types. Rectangle-oval- and late model small oval peanut ports. I have those 236 heads also.
And I agree with you. People are bench talking. Using larger volume heads to gain a few more horsepower at the expense of losing torque and response is going against the grain. With that fast velocity you can still run a long duration cam and keep your vacuum response.
@@antilaw9911 exactly! I had a flat top 454 with 781s and a xe268 cam and it might have been just as fast or faster as my peanut port street motors I’ve had but in a truck or a heavy car with 3.08 gears and a tight converter those big ovals felt a lot slower down low (where 90% of my driving was) I will admit though with the right cam,gears and converter the big ovals will make more power and be faster at the track!
Just recently purchased an old K30 Camper special Dually with a 454 in it. Appreciate you taking the time to get novice mechanics like me up to speed on the older specs and differences. Plan on taking your advice on getting torque out of the engine I have and switching the heads to match up with a 750 carb. Not looking to make rediculous power, just good torque for pulling 7-10 tons on a gooseneck.
I am building a 454 from a winnebago as well from 1978. It has the 781 heads on it. I'd say yours are 781s as well. Should make a beast of a pulling engine for you.
Yep, that Factory GM "Mystery Motor" was a very rare, exotic "short stroke/big bore/big block" engine, and something like only 20 of them were ever produced by GM, and distributed to Junior Johnson, who got 6 of em, Smokey Yunick got 6 also, and I forget who else may have got a couple, but I know that NASCAR rules required that ANY new engine HAD TO BE made available to the competitors ( only 1 or 2 motors each ) running Ford & Chrysler, so they could "inspect what they were running against". Junior Johnson immediately bought all the other Mystery Motors BACK from the competitors, except for Smokey Yunick, who kept his 6 motors. That way, Junior Johnson had enough of these motors to last the entire season. IT RAN LIKE A BAT OUT OF HELL. Junior Johnson led EVERY race using them, and if the engine didn't fail, they WON the race, just spanking the competition. But the problem was, the heads were plagued with valve train issues. If it lasted, it DID win the race, plus led the most laps during any race that it won.......if not, it LED the race until it quit running. Of course Johnson & Smokey built these engines to produce what Johnson claimed was around 800 hp, in 1963. There's a video here on youtube showing Junior displaying one of the actual race cars with this mystery motor set up for the big tracks ( Daytona, Charlotte, etc....the Talladega track had not been built yet ), in which the car had some serious innovations itself, in addition to the mystery motor. He stated that "Had the motor held together for every race, THEY WOULD'VE WON EVERY RACE THE ENTIRE SEASON, and he was being dead serious. Look for that video.
The mystery motor was the MARK III 427. A "Porcupine style" canted valve design. Quickly protested in NASCAR by competitors it disappeared for three years until a block showed up again as the MARK IV Turbo-Jet 427. 1963's Mark III- Deck height/rod length= Mystery. After Pontiac ceased producing their own V-8 in, I believe 1979-1980? They had some of their idle head designers churn out a few sets of Big Chief cylinder heads for the Chevrolet Mark IV. These may qualify as factory for restricted class racing. If you find a pair of those, buy them. They will out-do any factory iron 60's style head that the best port/weld skilled shop could turn out and many modern aftermarket alloy CAD designs too. The pinnacle of the factory cam in block- tall deck Mark IV head. Oldsmobile produced a limited quantity of factory webbed girdle alloy V-8 blocks in the early to mid 80's. Aimed at Drag/ Pro-Street types. Capable of displacements of 700 cubic inches just add the Big Chief Poncho Heads. Factory cam in block Mark IV V-8's became legend on Woodward Avenue-Take No Prisoners. Again, a very rare Chevy BB Variant.
thanks for the head info.in 1981 i got a 396 out of a 68 ss chevelle.i was 17 yrs and in NZ. it had oval ports , pop top pistons , steel crank all stock and was on original bore. I put a solid cam in 551 L 326 Dur headers and a 780 q jet .still got it . its well over 600 HP on Dyno.Love my old BB
1970 454 LS5 engines were rated at 365hp and LS6 engines were 450hp. The reason for the 402 in 1970 was emissions. Engines larger than 400ci had less restrictive emission standards and big block chevy's were NOT good with passing emissions. Therefore all 396's became 402's The 396 badges were marketing since the SS396 had become a legend.... and SS402 just didn't have that magic.
I know the emmissions issue was to do with the closed chambered head, it was horrible on combustion strength, so yeah that open chamber head along with the bigger bore was their solution.
You are sorta correct on the Mystery engine. It was more like Gen. 1.5 as it did NOT have a gen II bottom end. It was a block that was closer to the 348/409 blocks in design but modified for the gen II heads. So bottom end was truly a mystery as it was not a 348/409 OR a 396!
It's cool to see the "muscle" or pony car hp war again, I'm happy manufacturers have figured out great performance while still meeting emissions standards, best of both worlds! Thanks for your video, always appreciate your time and effort to teach us!
Thanks for making this video. I have a 454 engine in a Cabin Cruiser style boat that runs in the lower RPM ranges below 4200 and I was thinking of changing from the peanut port heads to the square or oval port. After what you've explained the heads I have seem to be the best to use for the most torque which is what's needed in my type of boat. Very good video, Thanks !
1st off: thank you for responding to a camshaft question I had for you couple years ago. 2nd, I later watched your video about choosing camshafts and it really opened my eyes to the whole cam theory. 3rd and lastly, need your advice yet again on another situation. Just acquired a '68 L78 396 4 bolt main for my 68 Nova. The guy through in a set of 390 (427 heads) and I bought a set of 990 rectangle port heads from him (which were actually on the engine, put on the engine at some time beings that they appear to be '73 year heads). So far from what I've gathered is that the large oval port 427 (390) heads are proven better for daily street type car situations (which is what I intend to use the car for). I don't intend on seriously racing this thing. Just want to give it some more power (the 'ol 267 4.4 is dependable as hell, just ain't cuttin' the mustard in the way of "performance driving pleasure"). Hell, you actually spoke of this in this video as well (power being made at low RPM's). And yeah, I've read it elsewhere too like I mentioned, but I've gotta ask you straight up exclusively because your really the only reputable guy I know (can think of) who really knows his stuff. So, I have to ask. For a every other day driver 68 (4dr at that) Nova, what would you recommend I put on this 396? The 390 oval port heads (which I'm assuming are "large oval port")? Or the 990 "hi perf" rectangle port heads? Very much looking forward to your input on this so that I know how to properly move forward with this project. Thank you for all of the knowledgeable videos you post. They make sense, are easy to understand and really help out folks like myself who lack the knowledge.
Good video. I was hoping you would've covered the early closed chamber heads. How do they flow vs. the open chamber head? I've heard a lot of different opinions.
Real good job on the video, I liked how you opened up with the big block history. I own a 1970 corvette and when I bought it back in 2007 it had a 350 sbc (it was not the original engine, but a factory replacement). It was OK but lacking low end power. I decided to build a big block, and build it from the ground up. It is a 540. The block is GM bowtie and the low-deck version of the 572. It has world aluminum heads with 310 cc intake ports to save some weight. Hydraulic roller with 248 duration at 50, and 650 lift, beehive springs. Motor is almost done and I can't wait to start it up (will be soon). It is EFI Accel Gen 7 btw also. Love rat motors!
E. Kitching Kitching: You might want to talk to a Corvette forum for correct chassis and axle modifications for your 70 model. An original ZL-1 from 1970 did not approach the power level your going to put in the chassis. Your potential for frame twisting and subsequently band-aiding and blaming weak parts is going to appear quickly with your larger big block's increased torque.
Aye Bee Thx Aye Bee, The frame was completely stripped down and most of the seams were welded up. I would like to put a roll cage in it but i do not want to tear half the car apart to do that. The rear-end came out of a '73 big block car and was rebuilt with new axles. The half-shafts are HD 3.0 units. I ended up rebuilding the trailing arms (major pain in the ass btw). We'll see if it holds up. Ed
Lloyd Stolworthy closed chambers shroud the intake valves and decrease flow. You can have the chambers plunge cut to “relieve” the intake valves and get the flow rate up to match the open chamber flow rate.... I have had it done to 66/67 702 CC oval port heads.
Hey man thanks for taking the time to share your knowledge...I just picked up my first "old school" 396 with the closed chamber oval port #3964290 heads. I'm in the process of gathering and researching parts to build a 375+ HP motor to drop in my street/strip 72 Chevy C-10. Your video's have been a great help in my resto builds of both my 72 C-10's..."Mouse to tow, Rat to go" Thanks again man! ;)
Getting ready to rebuild my 402 big block 350 horse power are the head on my motor large oveal port and can the larger valves be installed great post thanks for all the hard work you put into this and thank you for your dedication
Dude great video I was impressed on the new teachings. For me going to school to be a mechanic I still have a great deal to learn even though my dad is a master ase mechanic. Hey man thanks for taking the time to produce this sort video. Well keep your engines rockin and the tacs a knockin.
I believe the 396 was available in 1965 with 12.5 compression ratio rated at 425 h.p. They were called the nascar motor and was available as a crate engine to regular consumers . I Knew two racers that each purchased these motors . They were very potent and sounded very badass . Another friend bought a 66 chevelle , if I'm not mistaken , had that very same motor . I think this was called the Mark IV , or Mystery Motor , and some guys , back in the day , called it "The Nascar Motor".
True, but the 366 is a GREAT source for forged 396/427 crankshafts!! Because of the heavier truck pistons, the counterweighting on them is perfect to use them to build a 396 or 427.
kctransplant70 Agreed we used to buy them from the farmers where I grew up they would just buy a new 366 for their trucks and lay the worn out one out by the barn we could usually pick em up for 50 bucks
if you think an LS 6.0 liter truck engine is a stump puller, clearly you have never driven and have no clue what a 454 is capable of, or a 396 for that matter
Thanks for the "back to basics". I see your top commenter likes to take all the fun out of everything! I love the way he tells you that THEY are the experts while he goes on about how much of an expert he is! LOL! We all had to learn from somebody, as did all of our teachers. Not to mention that several others in the field arrived at the same conclusions running their own tests. He'd probably tell Gale Banks the he's just parroting someone else! I'll bet that won't smoke in his pipe very well... I also see that he has NO videos! LOL
@@Myvintageiron7512 listening on your statement on the Rectangular port head not working on the street below 3500 rpm. THAT would suggest they needed an equal length properly sized long tube header to make the work on the street.
My 66 2-door post Bel Air (Sleeper) is a 454 with 702 heads and it's a beast, it's got 400 horses on the dyno and that's with only a small vacuum secondary Holley. When those second two barrels open up all hell breaks loose. It's on my channel with a walk around vid. Great video thanks for your knowledge and time.
IMO the only great improvement in the new engines is fuel injection and coil on plug design. The basic engine have not changed enough to make any real differences. Lets face it folks; a carb engine with a nice came sounds better that an injected engine with the same cam profile - just sayin! BTW there is no substitution for cubic inches. If the block hasn't got enough cubes stuff a huffer on top and over drive it.
Got my BBC in my first truck almost 14 years ago now. Time for a rebuild and thinking stroker but don't wanna touch virgin steel and take that nostalgia away. She's a 72 with 781 heads in an 85 torque beast gonna be a monster.
You should do a video on the best casting #s of the 454 motor. I have been looking to build a 454 and I am confused about which casting is the one to get for the best performance with the 781 heads. Thanks for all of your hard work and awesome info!
I used to build stroker motors out of 427 hi-deck and this was before 502 or 572. Easy to build a 520 and still have thick cylinder walls. 12-71 with alcohol with 300 hp NOS and it would put a smile on anyone face. Unless they were racing you.
Two decades ago, I had a 454 from a late '70s pickup for my Malibu. I had an Offenhauser rectangular port intake for it. So I port match the heads to the intake not to far to break into the valve spring area, just to give a smooth transition between the intake and heads. I have no clue if ever I had performance gain with this, but the damn car ran great from stop lights to the highway, no issue in throttle response or surging at high rpm (4800 lol) So I wonder if I can do the same thing with my stock tbi 1991 peanut port engine in my K3500, if I ever decide to install a better cam, chip it and put the tbi unit on a performer oval port intake. Just to improve the performance a bit, without altering it's great hauling duties! Thanks for this very informative video! I'm a subsciber now!!
I happen to have a 402 from my 1970 Chevy Longhorn; that is one special, hard to find truck! Also, you reference rats and mice. Rats eat mice - that's it , that's all! Thanks for taking the time to make this informative video :)
402 also came factory in the Monte Carlo. Also I’m pretty partial to the Gen 6 heads for a street car. They flow pretty good and make good torque on the low end
Don't forget the ZL-X 427. It was essentially a ZL-1 with an iron block only sold over the counter, not as famous as the LS-7 crate motor, but popular in it's day.
Great informative vid mate. Cheers for taking the time to educate everyone on the differences. If anyone knocks you just ask to see THEIR video.... oh that's right, they won't have one. 😊 cheers again.
I'm up in the air between a cadillac 472, buick 455 or building a 454. I'm on a budget and it's going in a Buick 65skylark. I can get all these engines for under 400$. I don't really understand the difference between a screamer and a torque monster and the reason behind why one runs out of power faster. I want something strong, snappy and able to drag race sometimes.. Thanks a lot I always watch your videos and I've seen the 455 ones aswell
IF YOU ONLY HAVE 400 BUCKS FOR A MILL STAY AWAY FROM THE DRAGSTRIP. You will be embarrassed by some 16 year old kid in a Honda civic who has 2 grand in the headwork. BTW THE CADDY IS A TURD except for making a lot of torque. I will give you a grand for the Buick frame if it's a good one.
I put a 455 on my 84 K20, best motor ever for a truck. I never got around to it, but Mondo is a BOP motor specialist place, they make a stroker kit that makes it a 496. Numbers advertised are silly, if I remember right 510lbs torque @ 2800rpm. Awesome stuff lol
Ronnie Buicks u need to go watch the episode of power Block where they show the Defense between all the GM V8 and y the chevrolet V8 small and big block came out on top.
In the late 1960's many states were passing compulsory auto insurance laws due to the muscle car phenomenon. Auto insurance premiums were then and still are based on vehicle weight and horsepower. In order to make cars more salable, displacement and horsepower ratings were understated. Then came emission controls, dollar off the gold standard and the end of the draft, and muscle cars as well went off to the sunset.
John Lingenfelter found that oval ports out-performed rectangular ports by a good margin up to 800+ horse power. On a 454 with about 475 hp with rectangular ports the switch to oval ports added almost 100 hp. On a 496 with 560 hp using rectangular ports he picked up 70 hp switching to oval ports. The oval ports were 049 or 781's with larger valves, a port match and smoothing the short side radius on the intake port. I know most older Chevy guys know this so this is for the younger guys. Don't waste your time on rectangular ports unless you're building a 572 prostock motor turning 8000 rpm's in a 2500lb car. They just aren't good for the average high performance application.
I love it when you guys post good solid information, you are so right the 781/049 heads are killer street/strip heads and they make make mad power I have a few vids where I install the big stainless valves in those heads The most important thing to remember is they are open chamber heads and they have around 120 cc chambers this makes pretty low compression on a 454 you need a .120 dome piston for pump gas for around 10 to 1 more dome for race gas I love these heads I am putting them on my 502 with a .060 dome forged piston
Thank you. I bought a 1970 Corvette in 1995. It had a 454 that wasn't numbers matching and the seller didn't know anything about it except it was supposed to be a 454. Someone had ground the stamped numbers off the front of the block and tried to restamp it as a 1971 LS6? I took it to the dragstrip and it ran good consistent 13.40's-13.50's all summer long. That winter I pulled the intake(a factory GM aluminum) to find rectangular port heads. I then looked up the block and head casting numbers and the date codes and it turned out to be a complete 1970 LS6. I built a set of 049 heads like I read Lingenfelter doing and put them on it with a performer intake and a Crane grid hydraulic cam. My Chevy friends almost cried when they saw what I was doing. "You took the better heads off for a set of smogger oval ports" they would tell me. The next spring at the drag strip I ran a best of 12.21 with consistent 12.30's. Some of my friends shut up and took notice, others still to this day stick to the assumption that I made a mistake. I sold the 291heads in the local paper and a guy restoring an LS6 Chevelle bought them along with the aluminum GM intake. The money I got for that paid for the other parts plus a little cash in my pocket.
You're right Dave the wave. Remember the little over 700 horsepower solid roller big block Chevy blower motor oval irons vs. Square irons. The oval irons won horsepower and torque the square Port irons lost. The average square Port and 990 head had a 325cc runner it didn't flow to good and was too big. And remember when guys took cylinder heads ported and Polished stock heads and hurt the horsepower and torque they Dynod the motor after putting it back together wasted a lot of time and money and then to have less horse power and torque. I guess we've all seen people go to big carburetor intake cylinder heads cam headers and hurt horsepower and torque.
Great information . I have a 1995 Chevy Z71. It has 280K miles . I purchased it for a work truck. It has a 6 cylinder engine which may be why I got it so cheap. As I use it as a work truck hauling steel and wood, I was debating on getting a new truck or rebuilding this one. It runs fine, but I know its days are numbered and just researching so I know what to do when that day comes. Wish you were in Texas.
He's wrong about the 396 horsepower ratings. The 396 was introduced in the 1965 Corvette and rated at 425 HP, not 375. The 396 Chevelle came later that year. It was rated at 375 HP. It was the same engine as the Corvette but with a different horsepower rating. Very few 1965 396 Chevelles were built. In 1966 the 396SS Chevelle came into its own still rated at 375 HP.
Donald Smith That's right. The L78 396 (awesome engine!) was rated 425hp in the vette, 375hp in the chevelle and camaro. This might be more legitimate than it seems because of the difference in exhaust manifolds. The corvette had much better flowing exhaust than the others. But, throw a set of headers on any of them and you have a screamer of a big block.
Are you sure about that it was 425 instead of 375 on a 396 I'm a Mopar guy and I'm going to question that I'm building a 67 GTX by the way but just going through the comments Donald that kind of threw me for a little bit of a loophole I get back to me like to pick your brain fellow Gearhead Mopar or no car 67 GTX ragtop for Speed 440 balanced and blueprinted 4:56 gears with a 4-speed
I'm looking at a 57 Bel Air with a 454 and a 3 speed tomorrow. Your video has a lot of useful information. I love this, but I have no idea what I'm doing and I'm almost 100% lone wolf in this.
will schuck They are somewhat average truck heads, pretty good all around performance. If you want better performance- especially higher rpm- you want heads with numbers starting with 38, 39, and 62. There are many specific versions, but the above stated first numbers will be better than the later heads with 33, 34, 35.
hey i think it was a typo cause i have a 1977 454 and i just looked at my heads and there the same number as yours with 2 inch oval ports and i also looked for 366781 and that casting number is not in the gm castings theres a 336781 and thats the only 781 that start in 3 so id say your in the clear
In 1965, the 396 in a Corvette was 425 HP. You could also order a "drag pack" option in a plain jane Biscayne which included a 425 HP 396 and a 4 speed.
A couple more details about big block history: In mid-1965, the first year for the 396, it wasn't just the Corvette and Chevelle that was offered with a 396. The most common 396 was the 325 hp 396 (L35) that was available in the Impala/full size cars. I have one from a 65 Impala SS. It wasn't mentioned, but in 1970, the Chevelle was available with the famous LS6 454, 450hp engine. And a correction: The 1970 LS5 engine wasn't 440 hp. The 70 LS5 was produced in 2 versions, a 360hp(Monte Carlo SS454 and Chevelle SS454) and 390 hp for Corvette and full size Chevrolet. But the 360 and 390 hp engines were basically the same, with ratings measured at different rpm levels. So the output difference was just on paper, so they basically had the same output in reality.
great video. as far as what came out and when, people can do there own home work. I understand it's based off your readings and such, either way good job giving us an idea about the bbc heads and a bit of history.
Only one discrepancy in this video. You said that the Ls5 was 440hp. Actually you were describing the Ls6,and the rating was 450hp on that particular motor (conservatively). But I have have an awesome set of square port heads that I took off a 461ci because of the low RPM air velocity and people thought I was crazy for saying that I didn't need them on my street driven Chevelle. Enjoyed the video.
My vintage iron, I think your large Rectangular heads would run great on the street if you would pair them up with a long tube equal length header 36" primary length, probably with a 2.5" collector combined with a custom 2.5" dual exhaust and a x pipe. I discovered a while back while using a engine with a large head port that doing that the engine is fine on the street and you make power all the way down to off idle.
Thanks for the work. I know it takes a while to put something like this together. Not to mention that your dealing with a huge topic in only a couple of minutes.
You don't hear or see about it, but also in 1970 they made a LS7. It is the same engine as the 450 HP LS6, but with aluminum heads. I don't know the HP rating for these engines. The ones I have seen were in Vette's. Thanks for the info. Ronnie.
I'm trying to decide witch oval port i had on my 73 c10 454 pickup truck. I had my heads of due to compression failure in a sylinder. Turned out it was a hydraulic lifter that had locked itself at max, so the valve stayed open all the time. Wish i had checked the lifters before i took my heads off :) This is alot of years ago so its hard to say what i had. But i remember i thought back then that the intake ports looked huge.
I’d love to see a part two. Thank you very much for the video. It was really informative. This next summer. I’m going to be rebuilding a 454 for a 4 x 4 truck. Are any of the mid 90s 454 heads better than others? Thank you. God bless you and your family. Duane.
I see the 8.1 a lot on generators, gm really took over in the early 2000s for the industrial market. The ones I see run on propane or natural gas, and sit at 1800 rpm. The biggest gen they hooked to a 8.1 was a 100kw gen end. They went up to 130kw with a turbo. Fast forward another 10yrs and now they turbo the old center bolt valve cover Chevy 350 to replace the 8.1. I’m kind of impressed, I caught a glimpse of its rating somewhere and it was like 165 or 175hp at 1800 rpm.
Thank you for the informative video. I have a '78 Chevy k10 4x4 with the sm465 transmission. It has a good running 350 in it but my FIL gifted me a 1980 454 truck engine that has a B&M roots blower. I think it suffered from the wrong combination of heads and pistons as the engine tightens up when it comes up to temp. I plan to sell the blower, strip it down, bore the block and would like to build a naturally aspirated, appx 425hp, torque focused theme for the old k10. I've seen some interesting build articles using stock peanut port heads that seem to fit that bill perfectly for me. I recently had to overhaul the Cummins 5.9CR in my 2005 Ram and while I've always wanted to build my own engine, I didn't get to really enjoy it as I was under to gun to get my daily driver back into service. I'm really looking forward to piecing together a torquey old-school rat for my old truck! Thanks again for the video
I remember the first time I saw a 348 in the mid 80's, it was in a white 58 Impala at a gas station a couple miles from my house. I marveled at how strange the engine looked with those concave heads and valve covers.... I really wanted that car but the guy was asking more than I could afford. At the time, I never realized it was a big block.... I just thought it was a weird lookin small block. 😁
I've just acquired a 402 fresh build I'm waiting on the cam specs but it's a roller hydrolic and full roller rockers. It has the 781 heads. I figure it'll make really nice power around 400-425. It has factory domes aswell.
Thanks for the feed back really appreciate it. Yea would love to build a nice torque and hp motor and do that with the heads I have now planning on getting the eagle stroker kit was thinking of the 468 but it will cost the same so gna go with a 496.
The 502 had the same bore spacing as every other big block at 4.84 inches. GM has never changed the bore spacing, only the aftermarket has. The 1970 LS 5 had 360 hp in the Chevelle and 360 hp in the Corvette, not 440 hp. The LS 6 had 450 and only came in the Chevelle. As far as the rectangular port heads are concerned, they are exactly what you need in a 454 or bigger engine that is expected to turn 6500 and will reward you with sparkling top end power. The oval ports work fine but do not flow enough to feed an engine that is big and/or will have the cam to generate higher rpm and the expected high power up there. Remember that the big blocks, especially the 454 have a short connecting rod and a low rod ratio. This means that the engine can activate a large intake runner and needs enough volume to feed itself. Having the shorter rod generates better low end torque so the effect of too big an intake port is masked. Compare this to a 440 Mopar with it's really tall deck and really long rod. The intake runners are tiny compared to the Chevy square port runner. You can put one runner of a Chevy rect, port intake gasket over both intake ports on the Mopar intake ports. Don't be afraid of the rectangular port heads, the factory created them for a reason and they are the bomb on the right application.
Yes that's very good info and your right the peanut ports make awesome low to mid range torque they are somewhat comparable to the Dove-C BBF heads they make loads of low end torque to get those older huge cars moving.
Hi, my name is Michael. I thank Myvintageiron7512 for all the good inf. and hope he continues with the good work for the benefit of all of us that admire his work and good attitude. I also thank the people that send good inf with good intentions for the benefit of the rest of us. This is more of a question, but don t know were to go for answers. I'm looking for inf on 454 I bought from a mechanic and he could not give me any, as of what car it came from etc. I would like to know what kind of heads it has and what kind of block and any other things I could learn about it. I have photos of numbers it has on the back of the block and on the top of the heads. I will appreciate any inf that could be of help to find out about this motor. Thanks and keep up the good work.
The information on the oval ports is spot on except for the rec ports being better then ovals as far as design goes. if they are stock GM castings yes the rec ports will be better for racing however top fuel drag racing has showed that oval port cylinder heads have better velocity. like the big chief heads for example. but over all great info for the new guys.
