I agree, with the closed chamber heads I could check piston to valve clearance and then mill the heads to get 10 or so. According to the CR calculator I would need to heads down to about 77 cc's to get an even 10. Not sure what that means millingwise but might be possible. Sorry I misread the compression height on the 12 cc pistons so I would get 9.833 with the new heads and the 12 cc dish pistons and .050 quench.