[Chevy454]

The main thing you're looking for from the block (other than you're normal bore and journal specs) is "deck height", or "piston to deck clearance". I've checked several AMA specs, several tune-up manuals, service manuals, you name it, and Chevrolet has never given a spec for this. My theory is that they had specs for the other components to get the "stacked height" (1/2 stroke+rod length+pin height) and let that determine where your deck height fell. This leaves a pretty wide range from about .010" to .025", below the deck...I'll have to grab my notes to see the actual range. Anyway, this is a pretty crucial spec in determining compression ratio, and is the main reason you won't find a factory engine with it's advertised compression ratio. NHRA allows .008" below deck on the L-71/L-72/L-78/LS-6, and -.008" (above deck) on the L-88/ZL-1. I have always heard the ZL-1 was hand built at the factory and was "blue printed" there (like the W-31 cars), and got the -.008" deck height, but I've never torn into one to see if that's true or not!