Early on we used to use GE sigma or scorpion discs and calipers.( NOT the aust content ones) The discs are hat over and correct patern. The calipers have the handbrake . Simpily make up steel brackets to bolt them to at least 2 of the bearing retainer bolts. Dont forget to cut out the backing plate of the drum to use as a spacer between the bearing retainer and the axle housing. You will still fit 13" wheels.