I have a 1972 Gmc 3/4 ton 350ci, 4bbl, 4spd with ONLY 18000 miles.(old farmers truck) I want to know if anyone has info on converting truck over to a 4x4. Can it be done without doing a frame swap? Any info or posts would really help. I'm not scared to read and learn, just need to be pointed in the right direction.

72 GMC 3/4 ton 350 4bbl, 4spd w/ 18 000 miles (Yes, only 18 000 miles!!!)
1962 **** Unibody w/60 000 miles
1970 **** 1/2 ton Sport Custon
1976 Gmc 1/2 ton Sierra Grande
1982 **** 1/2 ton Custom
1995 Dodge 3/4 ton Cummins w/sweet power mods