Don Terrill’s Speed-Talk

Like a lot of people I have a copy of the Bill Jenkins book, The Chevrolet Racing Engine which was published in about 1975. Every once in a while I enjoy reading through it and it's very interesting to see where the small Chevrolet and really production based racing engines in general were in late 1974 when it comes to development. It seems that when the book was published they had been working on small block development for quite a few years and they already were cutting up and welding the heads, moving toward shaft mounted rockers, running the crankcase in a depression, very low tension/friction ring packages, many many areas.

BUT. What if a second book would have been put together and published say five or six years later... What would have been developed during that time? How would the cylinder head designs have evolved? They were pushing close to 700 horsepower in the first book with a dual quad induction but where were they by say 1979? 740? What do you think?

i worked for jenkins for a while in 98, he was still getting calls/ questions then about that book, he said he should of wrote another book- would of been intersesting for sure.

That engine design was tapped. Grump was apt at taking Can Am engine pieces and making them work pretty well in Pro Stock. SBC had no racing lineage. Just turned out to be a great bench mark. I think the biggest issue with the SBC was, it was so good it prohibited development of something better. Chevrolet did create a splayed valve head for Trans Am but it was never developed. When Grump put the SBC into the Vega he took a real risk. There were no Chevrolet aluminum SBC heads at that time. Cast iron surgery. How far could that be taken?

It's too bad no modern day Pro Stock engine builder hasn't put out a race engine book. Even a top team NASCAR engine builder book would be cool.

RAS wrote:That engine design was tapped. Grump was apt at taking Can Am engine pieces and making them work pretty well in Pro Stock. SBC had no racing lineage. Just turned out to be a great bench mark. I think the biggest issue with the SBC was, it was so good it prohibited development of something better. Chevrolet did create a splayed valve head for Trans Am but it was never developed. When Grump put the SBC into the Vega he took a real risk. There were no Chevrolet aluminum SBC heads at that time. Cast iron surgery. How far could that be taken?

The splayed valve heads were used on 358" SBC’s in NHRA Pro Stock Truck.
900 HP #’s were thrown around IIRC.

I took these pictures below at the Friday Pro Stock Truck qualifying during a NHRA event at the Texas Motorplex in 2001.

Guess who the guy with in the picture is. I would have loved to read a book by him about those SBC engines.

I later met him at that same event in 2007 or 2008. He was not Grumpy at all. I think he had a 500" engine in the car Dave Connelly drove around that time.(Pro Stock Truck was canned by NHRA)


.

i wish grump and smokey had written a thousand books each before they both passed they were legends who did not give a crap about money or knock off time and i personally would of bought all there books long live the kings

My question would be, If Grumpy was making 680 hp with a 331 from the parts of his day, why isn't it done on a regular bases with the parts we have available now...or is it?

2, if He was then why do guys here find it so hard to believe a 700 horse street 496 big block is near impossible?

I am not doubting the power Grumpy was making, that could be calculated by his et and mile per hour, I am questioning what was he making the power and or et with?...keep in mind the NHRA rule book has grown quite a bit larger do to the craftiness of guys from his day.

GARY C wrote:My question would be, If Grumpy was making 680 hp with a 331 from the parts of his day, why isn't it done on a regular bases with the parts we have available now...or is it?

2, if He was then why do guys here find it so hard to believe a 700 horse street 496 big block is near impossible?

I am not doubting the power Grumpy was making, that could be calculated by his et and mile per hour, I am questioning what was he making the power and or et with?...keep in mind the NHRA rule book has grown quite a bit larger do to the craftiness of guys from his day.

A 700 horse PUMP GAS STREET496. Building a 700 HP race fuel 496 is about as hard as pushing a engine block off truck tailgate.

The word STREET is very ambiguous at best.

lorax wrote:

GARY C wrote:My question would be, If Grumpy was making 680 hp with a 331 from the parts of his day, why isn't it done on a regular bases with the parts we have available now...or is it?

2, if He was then why do guys here find it so hard to believe a 700 horse street 496 big block is near impossible?

I am not doubting the power Grumpy was making, that could be calculated by his et and mile per hour, I am questioning what was he making the power and or et with?...keep in mind the NHRA rule book has grown quite a bit larger do to the craftiness of guys from his day.

A 700 horse PUMP GAS STREET496. Building a 700 HP race fuel 496 is about as hard as pushing a engine block off truck tailgate.

The word STREET is very ambiguous at best.

Yes, pump gas, Hyd roller.

I believe I read a while back that Grumpy thought his old 331 was making "around 600 hp", which probably means it was actually making around 550. Still really good for the parts he was working with. A standard AFR 227 head is way better then the max ported 292 heads he was working with, even with all the welding and porting.

A street 700hp 496 should be pretty easy to make. 800hp would be more of a challenge.

People have some funny ideas when the word "street" is tossed around.

GARY C wrote: Yes, pump gas, Hyd roller.

I think street car should also get atleast few month of daily driving without the need to do maintainance work. That it could be used on all normal driving conditions.

The 331 inch prostock engines were over 600 he reported the 355 nascar engines were at 550 with no welding on the heads or extensive porting.Those old 292 heads were pretty good for their day and if you think about it not bad compared to todays norm.

MrBo wrote:

RAS wrote:That engine design was tapped. Grump was apt at taking Can Am engine pieces and making them work pretty well in Pro Stock. SBC had no racing lineage. Just turned out to be a great bench mark. I think the biggest issue with the SBC was, it was so good it prohibited development of something better. Chevrolet did create a splayed valve head for Trans Am but it was never developed. When Grump put the SBC into the Vega he took a real risk. There were no Chevrolet aluminum SBC heads at that time. Cast iron surgery. How far could that be taken?

The splayed valve heads were used on 358" SBC’s in NHRA Pro Stock Truck.
900 HP #’s were thrown around IIRC.

It just occurred to me that you (RAS) are correct. Chevrolet never released the first splayed valve head for the SBC. I just looked up an old article I had on it.
The one used by Grump in Pro Stock truck and in V6 comp engines was a new different head.

Many years ago I street raced several different Mopars.
They had 383 and 440 engines with solid roller cams.
The 440:s gave 625 hp at 6000 rpm and the valve lift was .690" on the intake.
These cars could be driven to the races, once the transport truck for a long voyage broke 600km from home.
I had to tow the truck to a place where I could leave it with the race car and then drive the race car home, no problem.
With that cam and relatively low rpm there was no mantainance and the car ran 11.50 N/A and high 9:s with plenty of N2O.
Pump gas and 275 degrees plus duration allowed high compression, the most I used was 12.7:1 measured with a tilted engine in a stand.
Lots of my early ideas came from Jenkins book and up to this day nothing has been written that even comes close.
No nonsense straight on discussion sbout every part of the engine.
This I understand and know and that works but we don't know why.
Where do you find a book like that today, I still read it on a regular basis.
Other books never seem to touch the point you are looking for, they just go around it in circles.
I really wish that Bill Jenkins and Larry Shreib had done more books together.
I never liked Smokeys book though.

Erland