Engine swap
 

I have a 2003 Monte that had a 3.4l givin to me with no motor, no trans, body is in great shape, along with the interior, and everything else is intact. I have a 2002 Pontiac grand prix with a 3.8l runs and drives but the frame is shot, what do I need to make it run in the Monte, any help you guy's can give me is very much appreciated

Here's a list of some of the parts engine exhaust and possibly front pipe , all engine/trans mounts , all coolant hoses , air intake hose to air cleaner, complete engine with all accessories alt/ps/a.c./starter/ect. Complete wiring harness and computer and maybe someone to program PCM computer to match BCM computer . Probably forgetting a few pieces but that should get you started .

6th gen engine swap
 

Thanks Jeff, got a couple more questions can I use the sub frame that the 3.8 is already on and bolt it up to the Monte or are they different? I do have the sub frame that came out of the Monte and all the mounts, when you say complete wiring harness do you mean both engine bay and interior?

6th gen engine swap
 

what if I have both the PCM and the BCM from both cars can I just switch them over?

Not sure if the grand prix frame is same , my guess would be yes they should swap. As for the wiring you'll need under hood harness Not sure if you swap both PCM and BCM if that will solve problem or not, maybe the Maniac or bumpin96monte will chime in on that for you. Good luck

ok thanks, I appreciate the help

The subframe should be identical. AFAIK, it's only different for the LS4.

6th gen engine swap
 

ok thanks, I appreciate the help

I know the Monte uses an aluminum subframe, I don't *think* the frame is any different between the 3400 and 3800 engines (but I cannot be 100%). I know the Grand Prix uses a steel subframe, which does rot out.
As for the wiring, that's another topic, I would *assume* GM used the same wiring connectors between the two platforms.... BUT, again, I cannot be 100% certain. I know the Grand Prix and Monte Carlo, even though they are W-Body cars, they are very different in many ways.

I know this swap has been very common over the years. I am sure there are old thread here and on other W-body platform sites (of those that still exist) that discuss this.

As for the PCM/BCM.... Zero need to touch the BCM, leave that alone. But, the PCM, as I understand you would be best off using the PCM that goes with the engine, but you will want the VIN reprogrammed to match your car.