9" brake question

'72 and earlier 9" drum brakes all interchange. The '70-72 version has finned drums. The hardware kits changed late '60's too when they went from shoe retainer springs/clips, to the Bendix type pin/spring/washer type retainers. There were other changes in hardware too, such as self adjusters, but, if you include all the parts of a given year, they will swap no problem. The later setup is a superior design however.....at least as much as a 9" brake system can be called that.