reflash question

[passaphist]

i have a 91 c1500 with a lq4 swap. the motor is out of an 04 (not sure at this type of vehicle) and the pcm is out of an 02 (again not sure of vehicle. i have to ask the guy who gave them to me)

basically my question is will the pcm work with its current operating system or do i need to reflash? if so can i use efi live or hptuners to do the reflash?

im at the point where im finishing up the wires and then filling with the fluids. i just don't know if it will fire up because of the pcm issue.

thanks and sorry if its already been answered somewhere. ive been searching for 3 hours now and i worked all night.