brake swap from a 85 1 ton to a 69 3/4, is it possible?

[spinning wheels]

I have a question on brake swap. A co-worker of mine has a 69 3/4 GMC. He would like to put front disc brakes on his truck. I purchased a '85 1 ton flatbed truck for the motor and tranny. $200 bucks for a 454 and a turbo 400 (or is it a 475?). I was wondering if the front brakes off the 1 ton would be able to swap over to the '69 3/4.
What parts could I swap and what parts would I need to change (tie rods, ect)?
Any advise or knowledge conserning this type of swap, would be greatly appriciated.