I know it's more than just cylinder head temps that cause detonation, but it is still a contributing factor of course. That being said, does anyone know at about what cylinder head temp that the risk of detonation dramatically rises on an mostly stock L28ET? Or else, what head temp am I running the risk of melting/warping something?

 

Temp isn't that much of a factor. The motor can run very hot w/o any detonation. It depends mostly on correct timing & fuel mixture.