WM, If you've got the time, click on "Rebuilding a 92 R100GSPD" in my sig line. Venolia 1050 pistons mated to modded '77 R100S "squish band" heads at approx 12:1 (measured pressures, not cc'd). Torque, mid range power and fuel efficiency are all up by significant margins. Now if only I could find a way to control distorting cylinders that have been bored too thin to maintain dimensional stability... It never ends.