First of all, what do those Hyperchip/JetChip or performance chips change in the PROM? My uncle got one of those PROM burners for his 92 LT4 383. He was able to program a PROM for my other uncle's '86 350 TPI (not orig engine, but still TPI). I know you can change the fan turn-on temp, what else would be performance oriented that wouldn't harm the car? Spark advance/retard? Any PROM burner gurus out here? Oh and will the scantool for the '86 Vette work on my car? (He used it to fine tune the chip)

 

There's a whole PROM burner board here at thirdgen...

...but basically anything (except ESC) that was done for that '86 350 TPI could be done to our motors.