Made a deal with a friend for a couple of SC's, enough parts to hopefully make one nice one. I have read that the late blocks with the 3 5/8 bore have a different o-ring and lower block bore differnce from the older blocks. The '54 blocks have both been busted and repaired behind the carbs but I have older SC blocks that are unbroken. If I were to have the 3 1/2 bore sleeves from the older block bored to 3 5/8 and use the aluminum pistons from the '54 would I have an engine equal to the original or are there other differences between the old and new SC engines? Cam or crank differnces? how about the connecting rods? I know the carb is bigger on the '54 but how about the manifold? Thanks, sure there will be more questions to come when I get them home and start looking them over, Mike