No, when I was building my first one a person (I think it was on bigblockdart) told me that the blocks around 76 (H block I think) had thicker cylinder walls. I picked up 5 different year (some same) blocks and sonic tested the walls. He was somewhat right. I did seem that the block cast at and close to 1976 were a little thicker, BUT what they did have was more of a consistent wall thickness over the other years. Which would help with the overall strength of the cylinder.