If running a very tight quench, do you not have a problem with valves hitting the piston, at least on the exhaust stroke? I'm having a hard time picturing a very tight quench, or even pistons above the deck line not hitting valves, but I could be thinking of something wrong.

Taylor,

Two different things. Quench is piston to head clearance & p/v cleerance is between the valve notch & the valve.
But,,, you are right. If the p/v was close before & you raised the piston & didn't deepen the valve notch you can have a problem as obviously raising the piston will put it closer to the head & valves