Piston/Valve Clearance

[Alan Roehrich]

Robert, in all honesty, if the clearance between the intake valve and the valve relief in the piston is GREATER than the clearance between the piston and the head, you'll really have to have something stupid happen to hit an intake valve. For example, if the piston to valve clearance is 0.055", and the piston to head clearance is 0.38" total, they'll almost never hit, you'll have to spin it 9 grand in the water to make them hit, 999 times out of 1000.

Now the exhaust is another story, you really need at least 0.075" to be safe and comfortable.

All of this does of course assume you have really good valvetrain, 7/16" screw in studs, light valves, light retainers, excellent springs, and 3/8" x 0.120" wall pushrods.