Valve to piston clearance?

Thanks very much Duane. Looks like the described procedure checks at both 10 BTDC and TDC for exhaust, and both TDC and 10 ATDC for intake. And then says "This gives you your piston-to-valve clearance at the two points where the piston and valve are normally the closest." It does not look to be saying exactly +/- 10 are always the closest.... and that's not the be expected with all sorts different cams. But I'd think you're spot-on that it is going to be somewhere around +/10 degrees from TDC.

I use a similar procedure to what you linked.... I just rotate the engine a couple of degrees at a time starting at maybe 20 degrees BTDC on overlap, with checking springs in place and cam timed, and take note of how far each valve can open at each point. It is pretty easy to find at what degree points partially open valves have the least clearance to the piston, and get a measurement there. With performance type valve-reliefed pistons and modest cams, it is not a problem (that I have seen). Seems like the aftermarket piston manufacturers do a pretty good job of designing for this.