Moparguy: remember that gas engines run hotter than diesels. How much hotter is the question. I know that aircraft engine jockies spoke of 1300 degrees as a limit on 14 cyl radials but they have sodium cooled valves and valve rotators. I used to work on gas truck engines so equipped but they didn't have pyrometers so I don't know what the temps were. I do remember that sodium valves were very expensive!
