Well, the EGT gauge when it was working didn't go over 1400. Did it go higher on the last pass, I can't tell.
The reason I say nitrous eroded the 7 dents in the top of the pistons, is because it happened to us before. And some other folk, but I only talk about my truck.
We are going to take a 3 prong attack on piston temp: Oil, Water, Air, and cool all three to lower temps. We know the engine survived a nearly identical pass the day before without problems so it might just be the matter of 100 deg or less is the breaking point.
Yup, it sucks I didn't have working gauges.