67HEAVEN

OUR CORVETTE HERITAGE:
I know you'll agree that keeping our Corvette heritage alive is important to the hobby. As new owners come on board, I'll bet there's a lot about Corvettes that they don't know.

The OUR CORVETTE HERITAGE series of threads is an attempt to bring us all up to speed or remind us about the history and development of our favourite car.

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For the 36th in this series of threads, here's a bit of history you may have missed. This article, from 1970, reveals some secrets and little-known information about the all-aluminum 430 c.i. big block.

There has been lots of discussion about the old big blocks lately in C3, C1 & C2 and even in Off Topic. Those of us lucky enough to have one of the SHP or HD big blocks and/or to have been around in their heyday know the truth.....the rest of you - no drooling. :lol:

"How do these specs grab you: Well over 600 horses, over 550 ft./lbs of torque, revs to 7000, total weight under 500 pounds, high reliability, parts relatively inexpensive and readily available and a total cost, ready to run of under $6000 (including non-factory goodies like fuel injection)! These specs belong to this short stroke, big-bore 430-inch version of the open chamber 427 ZL-1 semi-hemi".

(NOTE: The emphasis on semi-hemi above is for those engine-builders who, in previous threads, claim never to have heard this term or the "porcupine-head" term before. I have at least seven articles from various publications that use these references......hmmmmmm :D and that's without looking very hard.)

This article appeared in the March 1970 issue of Hi Performance Cars magazine.

Enjoy!








P.S. Threads like this are not an attempt to minimize the amazing performance of later cars like the ZR-1 and Z-06. Technological advancement truly has been spectacular. These threads are simply to remind us all of the astounding performance that pure muscle (and not much technology) offered before many of you were even born.

May I wish you all a ride in a truly awesome big block ground-pounder some day. :D





[Modified by 67HEAVEN, 5:21 PM 5/11/2002]

richscorvettes

Bob,

Thanks for bringing these articles to the Forum. I always loved watching those Can/Am cars run. That brings back some great memories!

Rich Lagasse

MassVette

Your posts are greatly appreciated... Thanks!

67HEAVEN

Knowing that others read and enjoy them is great. Choosing what to post is the problem. So many articles....so little time. :D

DZAUTO

None of this is "new" to me, because I came from a time when "serious" performance was delivered by flathead Fords, OHV Olds and Cads. So, I am certainly quite familiar with the early day iron and alum BBs. I'm also quite aware of what has happened to V-8 performance as a result of hi-tech developments in recent years.
But there is one thing which I truly don't understand. Why hasn't Detroit married modern day technology with old time monster cubic inches???????????????? As EVERYONE knows (or SHOULD know) there is no substitute for cubic inches. NOTHING! Yes, you can increase torque/hp with such things as super chargers/turbo chargers. But in today's powerplants, this is basically only done with tiny displacement engines. Look at what dragracers have done with bolwers and 500+ cubic inches!
Why can't Detroit build a 450 cubic inch, hi-tech, twin turbo, all alum V-8 in a 2500-3000lb car? Then you could have the best of both, displacement and hi-tech.

67HEAVEN

Agreed.

"We've all heard the good news about the new Corvette Z06, reported to
be the fastest ever sold by Chevrolet. Probably true, in light of the tremendous improvements in transmission, suspension and tire technology since the 1960s....but, imagine if Chevrolet had put the same mega-dollars into thirty years of development on the 'Big Block' that they've been
putting into the small block! Where's my 2002 Corvette ZL-1 with all the technology thrown in??? Beep, beep. Move over ZO6!"

Above taken from the Personal Comment section of my website.

joe58

That is a nice article except that it incorrectly states that the Cam Am engine is the ZL1 production engine. The Can Am block was a different design then the ZL1 and produced with different tooling. The ZL1 used the 4.250 bore like the cast iron 427. The Alu. CanAm motor with cast iron sleeves block used a 4.440 bore siamese cyls design. Chevy also built a Can Am block without the cast iron sleeves and these were over 500 cu in. The CanAm BB Chevy motor dominated CamAm racing beating Ferrari, Porsche, and Ford, all who had more expensive exotic engines, until Porsche went insane and built their duel turbo 1000hp 12cyl.
The ZL1 block was used in the SCCA road racing Corvettes where the CanAm block was not allowed. The top drag racers were using the CanAm block not the ZL1 block. I asked Bill "Grumpy" Jenkins about this and he told me he used the CanAm block in his 68 Camaro Pro Stock car that he won the first ever Pro Stock race at Pomona in 1970. Beating the very quick Hemi cars in the new Pro Stock class was an amazing achievment. Pro Stock ran "straight up" with no class index like in Super Stock were the Hemi was much quicker. Grumpy told me the ZL1 block was "junk" (his word). After a few 8000rpm runs the HP would drop off significantly due to compression sealing problems. The ZL1 block worked ok in road racing (1970s) where they redlined about 6500rpm but the stronger Can Am block was needed for Can Am racing and drag racing.
The very successful 2001 Corvette C5-R endurance racing car used a 427 based on the GEN III LS1 Chevy production block. In my opinion, Chevy needs to produce this engine for the new Z06. Corvette needs at least 500 hp to be a competitive world class hi po street car. Viper, Ford GT-40, Ferrari, and Lamborghini all have 500 plus HP. A 2003 Corvette with 500 hp would make a great 50th anniversary edition. Maybe Chevy needs a few hundred emails to tell them what to build.

67HEAVEN

Would that be the engine referred to on the last page of the article (centre - bottom paragraph)?

Mac

I agree but, unless something remarkable has happened, the e-mails won't help. :nonod:

joe58

The article is about the Can Am motor but he calls it the ZL1 which many people did back then because of the ZL1 Corvette and Camaro. Chevy engineering R&D (AKA Chevy underground Racing) was doing research on alu motors which was also a way to finance an exotic racing motor for CanAm and other racing. Even to this day the motor is not well known but it is "The King" of all factory Big block Chevy's. Chevy was still making the CanAm block in the early seventies then had an arrangement which allowed Yenko to have some made into the 1980s. (I'm not sure on all the details) The ZL1 block was not strong enough and could not be bored out big enough to make the HP needed for Can Am and NHRA Pro Stock. The ZL1 used the 4.250 bore and crank like the cast iron 427. The Alu. CanAm with cast iron sleeves block used a 4.440 bore siamese cyl design. In 1968 it used a destroked crank to get 430 cu in. and about 650hp on gas. Then grew to a 465 cu in with a 427 crank, later they used a 454 crank to get a 495 cu in motor and made about 750hp. Chevy also built a Can Am block without the cast iron sleeves and these were 509 cu in then opened up to 524 cu in. Chevy engineering actually did use the Can Am motor for research using the same siamese cyls design on the 400 cu in small block and the Alu motor with no cast iron sleeves idea was used on the Vega motor. They used a cast iron coated piston to control wear. I didn't work out to well for the Vega.