[Gearhead999]

Mock up engine and put clay on top of piston. Turn by hand CAREFULLY, if you get resistance--STOP--. Then pull cyl. head and measure the thickness of the clay. You need about .100.

Or....put piston at TDC. Remove valve springs from valves. install head and measure how much the valve moves before touching piston. Subtract the cam lift, times the rocker arm ratio and you'll have clearence figure.