All three sets take a different ring gear and pinion. There are 2 sure grips that were available OEM. The clutch type (rebuildable with a kit) was available OEM through the 1968 model year. The auburn (spring and cone type rebuildable only with machining) came in OEM in 1969. They are interchangable from case to case with the proper side bearings for the sure grip unit. The clutch type is by far the best.