Question about engine fires

I recognize that this might be a simple question for y'all, but googling couldn't find this for me, and I was wondering: what is supposed to be happening when a moderate temperature engine under heavy load (in my case, an unmodded moonhawk 423 v8 with the drag radiator, no hood, and stage 4 supercharger going at about 330 kph at 4700 rpm in my "let's go for a land speed record" attempts) simply catches fire. The temperature is in the middle, it's in fourth gear, and suddenly fire.

What...

Question about engine fires