Quote:
Originally Posted by Kurt S
> 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.
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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?