I typically run .87 float and 4 clip position on a black slide in Houston. Lately, I’ve started monitoring head temp and trying to adjust float based on reaching an optimal temp of 385F. To reach this temp, I’ve run up to .89 float which seemed to get the temp in that range for practice but can’t tell temp for longer races. We are not allowed to run sensors for the regional races. I’ve had two engines run well with this approach but go from 98% compression to below 70% (leaky exhaust valve) in less than 10 hours. Below is a pic of one of the heads and the plug. Plug is white and exhaust valve is white. Is it possible the engine is overheating and causing valves to warp prematurely?