Hello, just joined this site in my desperate search for a PROM chip for my 1990 chevy 454ss.
It had an aftermarket hypertech chip that is no good, and I can't seem to cross reference it anywhere.

I went to the local GM, and my truck apparently doesn't exist. This truck is a 7.4l with a 3-speed, half ton short box. The only truck with this set up on their list is a ONE ton.

The truck has at the moment, a 5.7l so I need a chip for this as well. But they dont show any numbers for trucks with 5.7l's and a three speed.

I need a stock PROM chip for a 454ss (that the dealership can't even find) and a PROM chip for the same setup but a 5.7l in place of the 454 (temporary)

Here are the numbers off the front of my ECM (layed out something like this):

SERV. NO. 1228747 ATDX
86ATDX K300650694

16143781 ATDX