Hi, I have a 01 Monty LS. It has a 3.4 3400 motor with stock tranny. I love it and want to make it fast. So my question is this. Can I swap a 3800 into it? Will it fit, plug into factory harness,and bolt onto my tranny? I figure the pcm will have to be a 3800 but other than that what would be the process of doing this?

 

I think quite a few people have done it. You need the engine harness swapped also. Its not just a plug and play but its pretty simple.

https://montecarloforum.com/forum/en...ts-pics-14487/

 

Yes. Its about as easy as engine swaps possibly get since that year came with them stock. As mentioned above, you need the engine harness from a 3.8 6th gen, but that should be very easy to find as they were so plentiful.