OK, first off let me tell you about the car. I have had it for 10+ years. I got it for free back in high school for doing some yard work for someone. It was someone Else's parts car. I pieced it back together and drove it for a few years. I gave it mortal hell. Crashed it, broke it, fixed it etc. It was a POS then and is even worse now after sitting the last 7 or so years. It still runs and thats amazing with 300k! lol. Anyways now that I am out of college and a ASE master tech at a chevy dealership, I want to give back to the old firebird that gave so many good memories to me way back when. I picked up a 1990 firebird formula 350 with title problems. I want to stick the drivetrain from the formula into my firebird. I know whats involved in a v6-v8 swap, thats no biggie. What I want to know is wiring related. Can I just install the engine harness from the tpi car and the computer and go? or do I need to install the whole body harness. I am just trying to prepare myself for the big job ahead of me. Any insight will be GREAT!!

 

That's basically it.

You will need to replace the in-tank electric fuel pump as well, unless it has been replaced with a TPI pump (possible, but not likely).

 

I'm goona swap tanks from the formula to the v6 anyways as it has a new pump in it.

 

Good plan.

Are you swapping over the exhaust, or just going new?

 

The formula has headers and off road y-pipe so I am going to use those. And I have a 4th gen flowmaster catback on a 2000 z28 parts car I am gonna adapt to the 3rd gen.

 

Body pinouts are identical for 90-92 V6/TPI cars, so just like five7kid stated, just the engine harness and ECM

Swap it all and hit the road. Might want to snag the axle too since its available

 

Thats cool. and thanks for the help. I know you deal with these alot!