have a wrecked 89 formula with 305 v8. want to put it into 89 firebird with v6. 2.8ltr

 

Not too difficult if you have the tools and engine hoist. Swap engine and tranny together. Most wiring is the same, swap ECM and dash gauge cluster. Frame engine mounts will need to be swapped. Cruise control module from the V8 car. Radiator etc. Been a good while since we did this, probably a few things I missed. Nothing major. V6 exhaust might some smaller but will bolt up to the V8 converter. Nice to have both cars right there too.

 

Take virtually everything off the V8. If it connects in any way to the engine, it's usually different, all the way from the suspension to the exhaust hangers. FWIW, I'd take the crossmember, A-arms, springs, etc. Radiator, all the hoses, power steering gear, A/C lines, all the wiring harnesses, etc. Brake system, lines, fuel lines, etc. Otherwise lots of little things will trip you up.

The list of what is truly the same, is much shorter than the list of what's different. The power steering pump is generally the same, ignition module, some of the sensors... Not much else...

 

Excellent. My questions.
1. Looking at needing to take a 2.8L v6 and swap to 87 with v6 harness existing, any harness changes needed?
2. Do i need to swap ecm or can i just use my good tumble and swap the chips?

 

Like Drew said. I would start by completely gutting the V6 car then swap all the formula stuff over to that shell.