from 8.2 detriot to 12v cummins???

[katoranger]

I think it would be alot simpler than the 5.4 swap. Most likely will have to swap a transmission also.

[nevrenufhp]

Yes, it would be easier than the gasser swap. The 12 valve will have many trans options, which a wrecking yard can help with. While you're at it, you'll need some better gears in the rear end, because you wont need that many rpm to go down the highway anymore.