can 4.3 ecu be reflash to gen 3 v8

[96Mystic]

Sorry if this has be brought up before but a newbie on ls stuff. Helping a Buddy doing a 5.3 swap on his 00 s10. Making a standalone wiring harness for it. So we will be shutting off vats an all the unnecessary stuff too. But can we reflash his stock 4.3 ecu to a gen 3 5.3 settings?

[mecanicman]

2000 s10 is a vortec black box pcm, it cannot be flashed to control a 5.3. So if the pcm you want to use has 4 smaller plug ins on it the answer is no.