Opinions needed! I will be dumping the the old engine and tranny the first of spring. currantly on the hunt for a good supercharged 3.8 core and tranny w/ harness to go thru (strip,reseal build upgrade, chrome ect) milage is not a concern ...it will go all the way down. I need suggestions as to the best vintage or series to grab. (chevy/ buick /ponty...GTP) will the mounts need to be changed between the 3.4 and 3.8. also does the assy drop or lift out?

 

I'd say your best bet would probably be the Pontiac Grand Prix. They used the supercharged 3.8 for so many years, and there's tons of them out there. I'd say the Series II is most likely going to be your best choice. Lots of aftermarket for them.

 

Yeah, it would be easiest to find an L67 from a '97-'03 GTP. Try to stay away from the 1997 GTP motor, I've heard they are more "knock prone" than the '98-'03 years. I don't believe you need to change any mounts, but I think you'll need a 3800 wiring harness from probably a '00-'05 Monte. I know with the 5th gen L67 swaps, you need the 3800 wiring harness from a Monte Z34/Lumina LTZ, but I'm not sure about the 6th gen swaps.

 

I have seen the GTP engines all over, tons of recyclers with them. some come with all pulley driven assc/ wire harness and pcm. does anyone know if the montes header set up will fit the Gtp 3.8 or will I need to cut and weld?

 

If I'm not mistaken, MC headers SHOULD fit on a GTP motor - the only difference is the firewall clearance, the motor should be identical.

 

why didn't you tell me you want to do a L67 swap? i have ported M90 for sale and few misc. stuff. i can work out price with you. plus when i demod i will have more stuff for sale. as far as engine parts from the grand prix to the monte they are pretty much the same and will fit either cars. if you can afford the series 3 i do that other wise series 2 is just as good and cheaper to find.

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I wouldn't bother with the harness, getting an engine bay harness from another L67 vehicle is most likey going to be a waste of time for you. IMO, you'd be better off getting an engine bay harness from a 6th gen with a 3800 (non s/c is ok)- and just go on zzp and buy the L67 swap wiring adaptor (its just 2 simple plugs)- that way you know the harness will literally drop into your car, and it will also go on the engine with little modification.

IMO, I would just buy one with decent mileage (say under 75k). If you want to replace all the gaskets, and get everything cleaned and painted up- thats cool; but there really isn't much sense in rebuilding a 3800's bottom end- I'd just clean it up and leave it alone, it isn't a major failure spot anyways.

Plus, then unless you do some major mods, you could just clean the tranny up and drop it in too.


The H body cars have a handful of nicer things (like a better balancer), but its really not enough to mess with, although you may have to change some parts to make them work. As said above, the GTP's will be by far the most plentiful, so you're just as well off getting one of them. I'd try for a 99+, but 98+ is ok as well (they just got a little crappier TB)- don't even bother with a 97 IMO.


Upper and lower mounts are the same- just use the lower mounts that came with the new engine. You can either drop or lift it all out- it will come out fairly easily either way.

Specifically which headers are you looking at? All of the 3800 headers should fit a 6th gen with no problem- just as well as any other 2nd gen wbody.