Okay so I am day dreaming about what I want to do with my bonnie. Is it possible to swap the l67 out for a ls4 v8 out of a GXP GP or the likes? What would I have to do electronic wise to do it? Has anybody out there done anything like this? I know the 4.6 N* swap has been done so.....I am just brain storming right now so...no rush or anything.

My guess is you will need the transmission, engine, wiring harness, and PCM. The mounts will likely be different, but I'm not sure. You will likely need to do some custom wiring on the harness to get everything working. But with a good FSM and some time I'm sure you can get it all working. Would be a great project to watch unfold.

That is what I thought. I like the l67, but I want to do something different. I like the Ls4 motor and there is a turbo kit that will give you 600 CHP with stock internals, or at least that is what I have seen after some research into the kit....I don't think that would be practical though so.... What do you think would be the more livable, the LS4 with just the 330 chp or a modded L67 with more than 330 chp? I want the power but I also want the livability.

The 3800 will live longer than the LS4, also the transmission matched to the 3800 is better suited for it than the one on the LS4.

Umm correct me if I'm wrong but the LS4 uses a 4t65E-hd as well for fwd cars, just with v8 chains

The advantage of the LS4 is that you get an awesome exhaust sound while trying for 300+ WHP. I'm rooting for you! There'* a friend of mine who'* also planning this mod, and from talking with him I know it'* fairly doable.

Engine:LS4
Transmission: Custom bolt pattern 4T65E-HD with hardened internals
Wiring harness: W-body adapted to work with your H-body
PCM: Needs to be the LS4'* PCM with the proper wiring harness

It'* completely doable. I'd go for it if I were you. You're basically looking at an LS-series block with less internal displacement. This lets you switch around LS parts like an LS2 timing chain, LS6 heads & intake, LS-something cam, etc. There'* going to be some more aftermarket stuff available for your car, but exhaust is probably going to crop up as an interesting hindrance. With a turbo, that'* not much of an issue.

Go do it, and we'll help you at least by reading and providing commentary. I'm sure it'* a project that can be tackled if we all work/type diligently.

The LS4 already uses the LS6 heads and LS2 intake manifold if I'm not mistaken. Just port&polish those,throw on a turbo, an LSX cam and some flowmaster 40s and you're golden.

Use a trans built for street/strip use. The 4T65e is only rated for the 280ft/lbs torque the L67 puts out. You add the additional torque the LS4 puts out plus the added power from exhaust, porting, polishing and turbos. I don't think your bonne would be drivable for long. There are plenty of threads on GP forums about GP GXP'* with shot trannies because of the amount of torque they put out

I'm not bagging your idea. I think it'* a great idea that has crossed my brain more than one occasion and would love to see it happen

Look in to a 4t80 transmission. The other option is to build up a 4t65, and the cost of them might make the 4t80 a better option.

Doesn't the 4t80 have a stand alone computer to control it?