John, you really do need a plan going in before you do any milling. Your open chamber J heads ( not a bad head by the way ) are typically 68 - 72 CC's. You can use 70CC's when computing your CR. You will probably end up with zero ( or close to it - I always like to leave myself a little room - .005 to .010" down in the hole )deck height. Much of the info out there is based on zero deck height. 9 - 9.5:1 are good numbers to shoot for.