I have a 91 z28 and am having fastchips make me a custom chip, I am not familiar w/ performance chips or the cars computer. the order form needs the 4 letter PROM code. i thought it was these letters i found on a chip that is located directly under the metal cover u can take off on the ECM. there is a blue plastic cover over the chip and it has 2 circular holes cut out of it, which through one of them u can see this writing:

delco
AWFZ
5504

is the AWFZ the 4 letter PROM code?

 

You got it.

 

thanx!

anyone ever had a chip made from fastchips? i hear they are good. i guess we'll see in about a week when i get my chip.