[jerry moss]

the knuckles are different but will work, there's no place for the little 1/4 inch bolt that is on the disc backing plate. by the time you buy a part here and a part there it's usually cheaper to buy a complete assembly. if you want to swap all the pieces over to your existing housing then it would be a perfect time to replace all the ball joints, the little needle bearings in the spindles and the axle shaft u-joints--- if needed.
i always swap in 73 or newer parts as they are much easier to find and cheaper too. just don't try to mix 72 parts with 73 parts, the spindles and axle shafts must match each other otherwise you won't get a good seal where the shaft goes through the back side of the spindle. 72 and older uses a pound in seal in the rear of the spindle and 73 on up use a rubber flap on the axle shaft itself. the shafts are totaly different.