I've spent the better part of my free time this afternoon in the DIY PROM and other areas of this site and still haven't come up with a conclusive answer. You guys have made me miss my old cars, though ('82 Z28 with a roughly 300 hp 350, and a STOCK '89 RS 305/700).

I have two TBI rigs. One is a '89 V2500 Sub and the other is a '94 Jeep YJ (you don't want the specs) with a '89 V1500 Sub engine, harness, etc. I KNOW the '89 V2500 has the 1228747 computer and 'think' the V1500 has the 1227747 computer (at least from my reading today). The Jeep just needs to run respectably as it's an off-road rig and reliability is premium over power.

The V2500 is kind of a DOG compared to the V1500 and I did read that the 8747 computer is not 'ideal' for the 5.7L.

The QUESTION:--is the 8747 ECM and 7747 computer a direct swap (and will it increase my performance if I do swap?) or should I just have the 8747 programmed (EPROM chip) for my altitude{4500-8500 ft} and intended use (TORQUE for towing the Jeep item)?


{and thanks to someone for reminding me about this board....It reminded me I want a third gen convertible--}


..........{Oh, thanks for moving my thread. I was just going back to edit it and see if I could move it or not :blush:}

 

FWIW....

Customer comes in, buys a new ECM - I gave him an 8747 for his 2500 Suburban... just flashes the SES light.

Swapped with a 7747, worked great.

I believe something is different in the prom

 

Thanks. I guess I'll have a new PROM burned for my 8747.