SHP Small Block vs. Big Block

[Michael H.]

Re: SHP Small Block vs. Big Block

I wonder why these guy's all ran big blocks? Was it just a coincidence?

If I remember correctly, the first year small blocks were allowed in Pro Stock was somewhere around 1972??
There was something about minimum weight that required the big inch motors. I think that minimum dropped and that's when Jenkins built the small block Vega.

[Stuart F.]

Re: SHP Small Block vs. Big Block

Ridge;

There was a popular phallacy (sp on purpose) floating around back in the day that "Bigger was Better" (guess it even persists today). It was expressed often as "there is no substitute for cubic inches". I took advantage of a close friend's belief in that by buying his nearly new 290 hp fuelie engine out of his 58 Vette for a song so he could put in a 389 Pontiac. He eventually grew the Pontiac to over 500 cu in with twin Chevy tri-powers on a log manifold. He blew that sucker up so many times I lost count, and darn near took off his foot when a clutch let go (even with a scatter shield). I motored that 283 in two different cars for well over a hundred thousand miles with races almost every night. It even overheated twice and survived swallowing a hardened pin (one new piston), but never failed. It eventually was replaced by a new 327 by a buddy of mine while I was in the Army. He said that he'd never seen an engine so completely worn out - he couldn't save anything, but it never blew up.


Stu fox

[Ridge K.]

Re: SHP Small Block vs. Big Block

If I remember correctly, the first year small blocks were allowed in Pro Stock was somewhere around 1972??
There was something about minimum weight that required the big inch motors. I think that minimum dropped and that's when Jenkins built the small block Vega.

Mike, you're correct. I got a chance to meet up with Bill Jenkins a few years ago. I was told that the "advantage", was if you ran a big block in 1970, you were allowed to shave off body weight to the manufacturer's stated curb weight, which was always taken with a base motor. This was the era of "acid dipping" body sheet metal.
You are correctly stating that the rules changed around 1972 in an effort to favor small blocks.


History The National Hot Rod Association Pro Stock class emerged from the production-based Super Stock class in 1970 with a more liberal set of rules and an absence of handicaps. Rules initially favoured big-block V8s but by 1972 had changed to favour small-blocks to reflect contemporary trends in the American auto industry. In 1982, the NHRA implemented a new engine formula that allowed the big-blocks to return, due to the popularity of the Mountain Motor IHRA Pro Stocks with unlimited displacement in the late 1970s.

[Tom P.]

Re: SHP Small Block vs. Big Block

I've never been a pro pugilist, but I was a pretty good street fighter at one time.
I've carried over the same philosophy with the 56 (and some other cars). So far in street fighting trim, the healthy SB400 in the 56 has always come out on top. And with both tops and 1/2 tank of gas, it weighs 2950lbs.

[Stuart F.]

Re: SHP Small Block vs. Big Block

Tom;

Of course, you have the best of all worlds of performance; cubic inches and light weight. What combination did you use to arrive at 400 cu in? (specially relative to crankshaft). I know there are a lot of aftermarket assemblies out there as well as the "cast" factory crank which I never thought to be too durible for performance applications.

Stu Fox

[Tom P.]

Re: SHP Small Block vs. Big Block

Tom;

Of course, you have the best of all worlds of performance; cubic inches and light weight. What combination did you use to arrive at 400 cu in? (specially relative to crankshaft). I know there are a lot of aftermarket assemblies out there as well as the "cast" factory crank which I never thought to be too durible for performance applications.

Stu Fox

It's a .030 over SB400--------------with a Chevy cast crank!
Properly rebuilt and balanced, cast cranks are just fine under 6Krpm. Above that, you may be treading on thin ice!
With the light weight of a 56 (lightest of all 53-62 Corvettes), a 3.08 gear, and 400+ displacement, there is plenty of torque to compensate for the relatively high gear ratio of a 3.08. Especially a healthly built SB400!
By 5500 in 1st gear, it's gone, by 5500 in 2nd gear, it's disappeared!
And it is PURE NCRS (Not Correctly Re-Stored)!
Corvettes were made for fun, NOT for pleasing judges!

[Clark K.]

Re: SHP Small Block vs. Big Block

When I began this thread, my wish was that someone would dig out some old mid-sixties car magazines and look up the performance statistics. The two cars I picked are only 15 hp different in STATED SAE Gross Horsepower (375 vs. 390).

I love all the engines, so I have "no dog in this hunt". My suspicion is that the big block's extra weight and the difficulty launching it without massive wheelspin denies it a 1/4 mile performance advantage over a Fuelie.
-Clark

[Dale S.]

Re: SHP Small Block vs. Big Block

If you race a heavier car than yours race it up hill. If you race a lighter car than yours race it down hill. Old motorcycle saying from the 50"s . I always raced the Harleys on a strech of road that was up hill when I had My Indian Warrior, I won't get into the NHRA thing about big and small blocks. Dale

[Stuart F.]

Re: SHP Small Block vs. Big Block

Tom and Dale;

I like your way of thinking, but then we're from the old school and we learned from the school of hard knocks using good old American Common Sense.

Stu Fox

[Stewart A.]

Re: SHP Small Block vs. Big Block

In all out race conditions if you can rev up a big block they go like stink. The more cubes the better. All the fastest street registered cars in the 1/4 here are huge 600 plus cubes. So yeah they do go like the clappers. Stewy