article on 1956 SCCA Corvette with 1966 pre-production 302 engine
 

Interesting article on 1956 SCCA Corvette with 1966 pre-production 302 engine from Chevy Engineering

https://www.lsxmag.com/features/my-c...ts-1956-racer/

Great article that hits close to home in many ways.........

Tim

> an early, pre-production 302 with larger 4-bolt main bearing caps.
I didn't think 67 or 68 Z's had 4-bolt mains, even for racing. Someone will know for sure.

Guessing they were added, something like Milodon sells, the splayed caps for converting a two bolt block to a four bolt. Would not have been difficult for engineering to do a one off or just a few for testing.

Don't think any small journal small block ever made it into production with four bolt mains. Oops... just saw where it said "larger four bolt main caps". Don't know if that meant larger journals.... but then where would they get a large journal 302 crankshaft?

I spoke with Jim Swan of Motor Sports Research 20 years ago regarding his name being shown as a driver for a '67 Z-28 at the 1967 Sebring Trans-Am race. Motor Sports Research was the entrant and the car was declared a no-show. I asked him what happened. He said he spoke with Vince Piggins prior to the start of the season and told him he wanted to race a Z-28. Vince suggested to Jim that he contact Don Yenko and have Don build him one of their Stormer race cars, so that's what he did. Jim said he put money down and Don was supposed to be building him a white one. The car is shown in the entry lists as white and car #10. Jim said he was expecting the car to be there in time for the Sebring race at the end of March. He flew down and there was a blue car with Yenko sponsorship for Jerry Thompson to drive and a red one for Bud Gates to drive but no white car. Jim was furious and to my recollection did not get a satisfactory response as to why his car wasn't there so he backed out of the deal and never got his car through Yenko. A couple of months later, he did get a white '67 Z-28 from Jack Douglass and the car was disassembled to become a race car. Due to a variety of factors it was not completed until two years later when it was sold to Warren Fairbanks and two friends. I know that one of the Yenko salesmen or mechanics was trying to buy a partially disassembled white '67 Z and Frank Yenko wouldn't give him a good enough price so he bought a Mustang instead, mostly just to irritate Frank.

The same Motor Sport Research from Des Plaines Illinois on Oakton Street?

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Great thread and info, looking forward to more!
Anything MSR is cool also thanks for the great story too Jon.
:beers:
~ Pete

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:beers:

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The yellow Vega is still around. It is an early SRD chassis and was recently restored by a member here, Dan Stuck (ds1)

Back in 1992, I spoke to a fellow at a swap meet in Cedar Rapids Iowa, when I was picking up my first 1967 Z28. He had a pair of 291 '67 heads for the engine I was building for that Z28. We got to talking when I showed him the car, as I took delivery of the car at that meet. He stated, that he had personally seen a 1967 944 cast 302 block with 4 bolt mains, from the factory. He was quite certain of this. I had no doubt to not believe him, as he was an experienced engine builder and machinist. The heads I purchased from him were perfectly done, with 2.02 valves. Those heads are still on the CE NOS 1967 657 cast 302 short block I installed in the Gibb Chevrolet '67 Z "Little Hoss".

From what I understand, the 1967 Z production motors were 657 cast 2 bolt blocks. The 1967 944 cast block was a 1 year only casting, and reference books indicate it was a 283 block. Possibly engineering bored a few out to the 302 4 inch bore, adding 4 bolt mains for research?

I remember reading somewhere, but can't find the article, about the '67 302 motor development. The article said the 302 was initially developed in 1958 for the Corvette. The project was shelved, possibly due to the 327 development program?

I wish my friend Craig Schindler was still around. He worked in the high performance Chevrolet engine room, and helped build the '67 Z motors. I'm sure we discussed this but can't be certain if he confirmed some motors had 4 bolt mains. The early TRACO built motors for Penske would probably be the answer? If they used 4 bolt mains in 1967 and 1968, it may have lead to the 1969 production blocks with 4 bolt mains. Jon, have you any additional comments or information regarding early blocks?

Ken, I'm not too familiar with the 944 blocks. Chevy could do a lot of things like that in their engineering department so I could believe it happened. They did not put a 4-bolt main block in the homologation papers for SCCA Trans-Am racing until the 1969 season so it was not legal to run one of those prior to '69. If somebody did it, it might have been very sporadic because I never heard of a car being disqualified for that infraction. Over the cubic inch limit of 305, yes. A Yenko member here had a real Traco block short block that was built for Dana Chevrolet and Dick Guldstrand's Camaro. It was sold to Tomy Drissi who owned the Guldstrand Camaro at the time. Yes, it was a 2-bolt main "657" block.

The actual pins and and then the big ends of the rods were more of an issue than the mains in 1967, weren't they?
If you're gonna get busted for something it would have to be going out of spec in prepping the early rods.

I have a 327 that was built in the 1970's with the Summers Brother splayed billet four bolt mains.

There was a lot of development done on 301 Chevy racing engines before 1967 and was not hard to do a 4 bolt main conversion

It also could be a mis-remembrance that got recorded....