What specs do you want? 1969 383, punched .070, pistons Silvo-lites 1276's @ from what I'm told CR is suppose to be around 8.5, from what I just looked up it's 8.0. Now mind you that's with a 440 block. I'm not using a 440 block however. I'm using a Lo-block 383 with stock 383 crankshaft. I'm taking the advice from here and getting the Jegs Stealth heads. I have no intentions of " zero decking " the block. Now the Tech there stated that I could go as high/big as .600" lift cam and be safe, ( no intentions of doing that), so my compression rate should / could be as high as 11.0-1. Minimum of 10.5-1. That's as far as I've gotten so far. Did that help you any? It's as much that I can divulge.