I re-checked my calculations. I am right a 10.13 with a 70 cc head and no quench (.080). That is with a .027 thick gasket. If I mill .050 off the head the compression will go up 1 point. I believe that is too much for a iron head on pump gas. I read the info Polyspheric posted..... good info. I will buy a head gasket and see what I can come up with. Playing with the numbers I need roughly 10-11 cc less than I have if I mill the head to be closed chambered and have .033-.035" quench.