I worked in Chevrolet parts in '67-'69. As I recall, I think there were some large journal crank 327s, but no 4-bolt blocks. Warning: My memory has failed on rare occasions! :-)
We sold a lot of 375 HP 3/4 motors to the local Illinois dirt trackers. They would add a roller, port injectors, and a mag, then drop them into sprint cars. They were 2-bolt blocks.
