I found an engine
So I found myself an engine. It’s a 3800 series with a boat load of mods including custom fabbed aftermarket parts. Car had a fire, and the engine bay was spared. 17000 in custom work on the engine and I bought the whole car for 1500. From what I’ve been reading, one of the only things I won’t have that will be necessary for the swap is a new PCM wiring harness. The engine is coming from an 03 Monte Carlo and going into my 2000 with a 3400. Am I correct in my research so far that the PCM harness is all I’ll need? Thanks! Any help
appreciated.

 

Either someone is pulling your leg or that's the most expensive 3800s on the planet.

Any pics or a mod list to share?

Regardless, 1500 isnt a bad deal for a good, complete powertrain these days as long as the mileage is fairly low.

I'm not particularly familiar with the 6th gens, so I can't really comment. One note I'd make on the engine bay harness to make your task a bit easier- you can get a 3800 NA (L36) engine bay harness instead as thatll be much easier to find. The difference to the supercharged engine is only 2 plugs, and they sell a cheap adapter harness. I just think you'll have a far easier time finding that than a L67 6th gen harness.

Maybe an ignorant question, but can't the harness from the 03 be used?

You don't mention the plan with the transmission, but if you need to mate up a transmission, keep in mind that the L67 uses a larger diameter torque converter from the factory. If it was that heavily modded, it most certainly had an aftermarket converter mated to it (which is the smaller / standard diameter). Just something to be cautious of.

On that discussion- whats the deal with the transmission - you didn't mention it at all? You said you got the whole car, so hopefully it has a fully built transmission that came with it. If the engine is really a max effort build, youre going to have a very hard time keeping a transmission together behind it unless that transmission has the best of the best parts in it (ie the whole package of discontinued GM Racing goodies).