[trukman1]

Any 67-72 4x4 frame should work fine. The problem with converting a 2wd frame is that the frame is wider at the rear. Not only that but it will be wider at the rear spring hanger than at the front. One easy idea is to find a GMC frame. While most Chevrolet frames came standard with coil spring rear ends, GMC trucks came standard with leafs. There is a post somewhere on this site where one very talented member in AK put his on a newer Yukon frame, IIRC. I'd be intimidated at something like that though. Good luck.