12 bolt rear from 77 3/4 ton truck

[onelow69]

This is the question's that I have. 1. Can a 1977 3/4 ton 12bolt go in a 69 1/2 ton. I know that the housing is wider and it is 5 lug and the brakes are bigger 2 1/2in instead of 2in wide.
2. Is the width the same as 71-72 trucks. Because I want the wider housing so I can have the right backspacing for the rear wheels.
3. Who makes housing pads that I can weld on. And I know that I would have to cut and grind the shock brakets off and old spring perches.
4. Would I have to change the P-Valve. Because I already changed the front to disc brakes and have the right P-Valve for the set-up that I have.
5. Will the emergencey brake cables work from that rear to my stock set-up.
If there is anything missing please infourm me, because I have a chance to get this rear end for 25$ and Its in great shape.
Thanks onelow69