my 2000 lumina needs a swap from 3.1 i need something more aggressive and the 3.1 is got some problems that keep coming back like i miss on cl 3 but it comes and gos i cant seam to fix it so if there is another motor i can fit in there what would it be

 

You can either get a 3400 from a 2000-2005 lt monte carlo and it would pretty much drop right in and plug right in and you would need either a tune or a 3400 PCM. If you want alot more power you can find a donor lumina/monte carlo with the 3800 in it and swap the engine, trans, axels, wiring and PCM, maybe just take the whole engine cradel and bolt it in and then just swap the wiring harness for the one from the 3800.