Yeah the Max compression I can get out of these numbers 383 blocks, is 9.65 , using KB400's and the stock 906 heads. That's good enough for a resto project. Now the A990, Stroker, is a completely different matter. I'll probably go for 10 or 10.5, and try to keep a dynamic of 8.5 , to use pump gas, but that motor with breath very deep, with the other ingredients Im using. :thumbsup: