Hy gary c, I don't have a parts book which covers light duty up into the 70s, which is when front disc brakes began. According to one of my brake catalogs the hub and rotor for the dual rear wheel truck are the same from 1974 to at least 1986, the calipers are the same from 1979 to at least 1986 (the last year of my catalog) This does not address whether the disc brake steering knuckles are adaptable to your upper and lower control arms. One thing I did learn (by experience) the disc brake knuckles are thicker on the bottom and possibly the top, than their drum brake counterparts, so you'll have to buy ball joints for disc brake application, sorry I cannot be more definate than that.