The Stovebolt Site Forums The Shop Area Engine Shop Rebuilt 235, but has sat

I believe they did that as a method of making some parts interchangeable between several engines and car lines. For instance, the 292 6 cylinder runs the same connecting rod journal size and rod bearing as the big-journal small block Chevy crankshafts. We used to make 3 9/16" stroke small blocks by offset-grinding 350 crankshafts and using the small journal connecting rods and pistons with a shotrter compression height. A lot of parts sharing between engines, and even car lines began in the mid 1960's, about the time the 3rd. generation Chevy six came along. The 4 and 6 cylinder Chevy engines even got the same bellhousing bolt pattern as the V8's, and automatic transmissions got dual pattern bell housing bolt circles so Chevy and Buick/Olds/Pontiac car lines could share transmissions. About the same time, GM consolidated the engine production to eliminate duplications between the engineering departments of the individual car and truck lines. I believe it was all a cost-cutting effort to make GM a more efficient auto maker. At one time, Buick, Olds, and Pontiac all had different 455 cubic inch engines, and Chevy had a 454. Not exactly a good way to control costs, but each car line had independent engineering and R&D departments.
Jerry