What is needed to switch from sbp to 67 and later style wheels

you can buy adapters that take your current 7/16" right and left hand 5 on 4 lug setup to all 1/2" right hand 5 on 4.5 but... those adapter must be properly installed. Odds are the balance weights welded on your break drums will interfear with the apapters mounting flush against the drum so some notch grinding on the adapters or relocating the weights will be required.