They put a 50 hp shot on a 5hp briggs & stratton hp mower (looked pretty new), and the thing would fire up normally, and then they'd hit the nitrous, and it would wind out then burn up, and then stall. But then they would just go and start the motor again, and do it again, and again, etc... and it just says to be continued at the end w/o the motor really dieing, just revving out then stalling, over and over.
It seems like it was just flaring out somehow, and not just burning up the head, or popping the rod/crank. Though I could just imagine that thing blowing a rod and shooting the head out into orbit... ;D
~Bill