Originally posted by Max Keith
When you clay the pistons to get an imprint of the valve, measure the imprint with a micrometer and you should have a minimum of .050" thickness.
That's a little too tight. Most of the time, .100" minimum for exhaust, .080" for the intake is recommended.
However for your application, your lift, duration, and timing events tell that you will have no problems, unless you install the timing components incorrectly.