I ran duallys on our 64 c20 but i never could find the proper lug studs. the longer ones that where the same diameter did not fit tight enough in the hub. Wheels stayed on but when i tried to remove the lug nuts the studs turned in the hub. Also the later wheels wouldnt work properly because the later trucks used a larger diameter wheel stud. Also there was a shoulder on the 3/4 hub that a early wheel wouldnt fit over too tight. Next time i try it i will use a 73 up rear end. or redrill my 64 hubs to a larger stud diameter. OldWolf