I need some advise, I am currently home porting a set of Gt-40p's. I am going to fit larger valves 1.94/1.54 (stock 1.85/1.46) and I want to mill the heads to up the compression ratio to a something similar to the 220kW AUII heads. I think the P's are a 59cc chamber, WHAT IS THE E7 CHAMBER CC?? I'd like a compression ratio of 9.45:1, how much would I get milled off around 20thou? I read that the rough estimate for a small block Ford factory type casting is 1cc for each .007" milled?