what I would do is find/buy a good 742 sure grip in the ratio you want & you're set. it would have the desired clutch type from the factory & highly likely that has not been swapped (if you see no springs in there you are golden). I highly prefer a ring gear felpro gasket as opposed to using RTV. some heavy parts house gear oil (I forget the weight) with a bottle of furd sure grip additive. set your axle end play to .010