blownrunner

Are all the engine ECM's interchangeable for our ZR-1's? I am thinking the PROM chip could be swapped in the 90-93 cars, so those years will be interchangeable. What about the 94-95 cars, as I believe they do not have a removable prom? I have a 1991, BTW, thanks.

WVZR-1

All LT5 ECM's have removable PROM's - none are OBD2 compliant and can be programmed like the LT1/4. It's generally accepted that the PROM's are "year model" specific but recently there's been mention of wider "year/model" usage of the ECM's is possible. I've no "first hand" knowledge in attempting changes so I won't comment on that. A PROM may have an overlapping application after updates that were compiled but I believe each model year started out with a specific PROM for that model year.

Dynomite

Marc Haibeck did some testing.......ECM Interchangeability TIPS

LT5 Performance Calibrations

95ZR1

Yes, my '95 has a removeable PROM. So the PROMs are
year specific, but the ECM's are interchangeable. Good
to know. Great work, Marc!