Im no expert but I'll give my opinion any way... I would think that with 100+ pulses of super hot gasses going back and forth in the gas port holes it would tend to heat up that area of the piston more than if there were no holes there, this would be fine for a drag motor where it runs WOT for 8 seconds (or so) but something running WOT for miles on end at a very ihgh output level it may just be too much especially if your tune is not perfect. The area around the hole is already a weak part of piston (ring lands) and the sustained high heat is just not a good combo.