I currently have two cars, A 1986 Trans am 305 carbed with a 5 speed stick and a 2.8L fuel injected automatic 1989 firebird. Well the problem is that the rust damage to the 86' is extensive and will cost me more then what I paid for the car to fix. But my 1989 Has NO rust on it at all.

I want to swap the 305, trans and shifter into my 89' Bird. using the 86' as a doner car.

Now I was reading some of the threads and it talked about always wanting to swap from a newer car into a older car. what problems will I run into trying to swap from the 86' to the 89'?

Will I run into VATS problems and computer problems?
This Is my first swap and I have a mechanic buddy who mostly works on older stangs. so he doesn't know what problems would be over the hill as well.

Any answers or suggestions would be great.

 

First be aware that it's federally illegal to put any carbureted engine in any '89 f-car. So, if you live where they do smog checks, you'll have to put EFI on the 305. Preferably TPI.
And if you do that, then neither of your wiring harnesses is any good to you.
Otherwise, it is a lot of work, but if you use the '86 electronics in the '89 shell, then the VATS won't matter. '86 didn't have VATS.
If your '86 is an L69, then also swap the rear axle. If your '86 is an LG4, then keep the V6 axle.
Also, plan on swapping all 4 springs, both sway bars, and the steering box. the T/A stuff is much better.
Unless money is ultra tight, don't swap the exhaust. Just get new aftermarket stuff. Headers, cat-back, and such.

 

Even with the carbed engine, the 89 VATS will kill his starter unless his module is powered and the proper key inserted. A common resistor bypass or simply bridging the relay would solve the issue

 

Not back then. The vats had nothing to do with the starter in my sister's '90 Firebird V6. I spent weeks on the vats until I got the resistor right, then it would fire. But from day one it would always crank every time. And if you change the computer to a pre-vats computer, you can just remove the vats wiring entirely.

 

http://www.austinthirdgen.org/mkport...m_pass-key.jpg

The starter relay is independent of the ECM and just as easy to bypass when the old ECM is removed. Unless he changes the module and/or key it will still function correctly

 

good luck hehe