looking to get the most out of 4.8 w/ 862 heads. going to give them a mild p&p and mill/ gasket to get compression up. how much can be remove w/o having ptv problems. would like to get around 10.5-11:1. cam in sig. i'm thinking of a .030 gasket and mill .020 off heads. total of .044 off. worried thats to much. according to calculator that should be around 10.5:1. anyone ever taken that much off.