Quote Originally Posted by kilohertz View Post
Thanks guys, appreciate all the info and advice.

Were the 7427 only available in '94-95 trucks/vans? Are there any tell tales signs for the vehicle to indicate it has this ECM as opposed to other ECMs from the same dates? Saves pulling a lot of glove boxes off the hinges. i.e. VIN codes or glove box VIN stickers.

Also, while I have your ear, in the 7747, does the BLM data get deleted when the battery is disconnected? How is it stored in the ECM? I have been removing the battery cable every time I change the PROM tune, not sure if that is detrimental or not. I suppose I could be extra careful putting in the chip and leave the battery connected if need be.

Thanks!
My 1993 Suburban at some time in it's life had a dealer replaced ECM, and it was a '7427, so I lucked out when I bought it, swapped in earlier crate engine and started tuning.