Dually Axle on a 1970 c20

Hi guys I am looking into swapping a Dually axle with my Single wheel axle and I am wondering what will need to be done. My local junk yard has a 88 chevy 1 ton with a dually axle for a couple hundred bucks so before I go pick it up I would like some input from you guys. My truck is a c20 3/4 ton long bed camper special.