a stock one will have hard time living behind even a stock 6.0, unless yuo plan on driving it easy you will need to to the following to the trans;

Beast sunshell, with wide sin gear bushing, rebestos 3-4 clutch pack, carbon 2-4 band from patc with corvette servo, bittet 4th servo, borgwarner sprag, depending one the converter you choose, and hp goals with the 6.0, you will need a mega valve and oversized reverse boost valve, high rpm pump slide spring.

I'd say anything over 360rwhp in a truck you should think about the hardened output and input shafts....price adds up quick for a 700r4 to hold power, but it can be done.

Also stay away from pre-87 7oor4's i think they have weaker input drums and lower volume pumps, not sure on the exact details though