454/400/NP203 to 454/700/NP208 Swap

[Misled]

OK, I have searched for this answer, but can't find anything for sure....

My buddy has a 1979 Chevy K20 he bought brand new (yeah, I'd like to have it!!) The only drivetrain change is the swap from a 400 small block to a 454 big block. It has the 400 auto trans and 203 full time transfer case.

We found a nice 700 auto trans with a 208 transfer case from a mid 80's Blazer. This truck is more of an occasional driver with the even less often need for 4 wheel drive.

My question is........what issues will we encounter swapping them out? These are the areas I thought about;
* u-joints (are they all the same)
* crossmember (will the 79 one work)
* driveshafts (will ones from a mid 80's K20 work without modification)
* column shift linkage (will the 79 stuff work without modification)
* cooler lines (really not a biggie in the grand scheme of things)
* speedo cable (will it hook up OK)

I may have tons more questions.......AND I told him I would post the question here and that you guys were the absolute truck experts!!!!!!

Thanks a bunch!!!

Misled