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Discussion Starter · #1 ·
So i currently own a 2007 Grand Prix GTP, and in the future i would like to pickup a N.A. Grand Prix. Can I not just take the heads, ECM, intake and supercharger off of my GTP and put it on a N.A. GT? I know its not the "HD" transmission in it, but I've heard there's not that much of a difference anyway. I've skimmed through discussions regarding this and have heard some mixed feed back. anyone who knows anything about this particular issue please let me know their thoughts., thanks.

And no, I'm not wanting to go and do a motor swap it simply isnt worth it at that point. My GTP already has 220,000KM on it with original motor so I'm hoping to find a GT with lower KM on it with a body that is in good shape.
 

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"Top swaps" like that are incredibly common to do. As long as you can get all the required parts sourced online or from a junkyard, you should be able to assemble it just fine. There's a handful of videos floating around YT on the topic, and most likely some step-by-step guides still archived somewhere.

Your main concern will be getting the computer tuned to be set up for proper calibration of the fuel and spark tables, among a few other details. Reprogramming the original PCM in the car is usually best, since you're leaving the transmission and harness basically alone.
 

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Discussion Starter · #3 ·
I think you may have misunderstood, I currently own a GTP with high so I wouldn't need to source any parts, I'm just not sure of everything I would need to keep to swap over to my newly purchased N.A. GT. Ok so what if alternatively I just kept the ecm and the majority of the sensor's from my GTP and put it in my GT?, Ill just keep what I need from the GTP and buy a GT. so let me Reword my question: what would I need to keep from my high mileage GTP before i get rid of it and purchase a low mileage N.A. GT in order to convert the N.A. GT into a supercharged 3.8?
 

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Ah, so your GTP is rotting away, and you want to use it as a donor car for a fresh GT top swap.

First, I'd hang onto the entire engine, if possible, because the blocks are extremely robust and last 300k+ under abuse, if not blown up from bad tuning. (if you were closer to Nebraska, I'd offer to take it off your hands to add to my spares, but unfortunately not)

As for just using a stock GTP computer, there's just enough differences in a top swapped GT to cause some headaches. Watch some videos of Terrell Smith on YT setting up his white 2005 build last year. I sent him a GTP harness and everything, but he wound up having the best success with the original GT harness, PCM, etc. and tuning in the settings for fuel/timing/etc. in that file.

That brings up the final point, which is that all of these types if swap-a-roo's possible with these cars tend to assume the fact that you'll have a PCM tuner like HPTuners to get things working properly (or possibly DHP for old timers here). In the early 2000's, it was possible to slap enough piggyback electronic widgets and parts on these cars to cover for most custom work, but in the newer generation (04/05+) cars especially, the need to make the PCM/ECM/TCM/etc. say the right things is even more critical to make it run right for the long haul.
 
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