You more than likely will need to relocate the spring perches on any rear end you retrofit to your truck. So look for a gm rear end (5 or 6 bolt, whatever you prefer) that is between 61 and 62 inches wide from flange to flange. I installed a 12 bolt out of a 65 1/2 ton (6 lug)in my 49. Fits great. I did a 54 with a 84 trans am rear that had disc brakes on it. That also worked good. It even had a sway bar on it. Good luck.
