I have a 2008 grand prix, blown engine, transmission slipping. 3800 Engine and has no turbo.
I also have a 2002 buick custom 3.1l with transmission and pcm. Car has been good but frame is gone.

I know they are of different animals, but i want to take the engine, tranny, pcm and transplant into the grand prix. Maybe it could be called a Grand Custom?
I know there will be headaches. Motor tranny mounting. Will there be signicant differences.
The wiring. Having the pcm will I also have to bring over the engine and tranny harnesses?
Which now what about gauges?

I know its crazy, but i am cash poor with tools, equipment, and friends (which I may lose). Before I start what problems will I encounter. Like it or not this will get done.
Any input would be appreciated. Don't say don't do it, etc., I don't need negativity.

Have hope.

Well . . . they're both W-bodies, different generations. I'd bring the entire wiring harness over from the 2002 to the 2008, including gauges.

The engines are not related at all. I believe the transaxles have different wiring as well, although they are related.

Definitely going to be interesting!