If my memory serves, you'll learn the axle bearings and other design changes will prevent this interchange. Entire late model 7.25 will bolt right in. these with 276 gears are still quite common and available too.
Yea i just checked and the 74 model has 5 and the 63 has 4 bolt flange,The pinion bearing is bad in the 74,Is it hard to change the bearing.that what i was going to do till i found out the pinion bearing was bad........
No.
74 has a larger bearing and the axle tube gets larger at the axle bearing end, also uses the same backing plate as 8 1/4 , 8 3/4 & dana.
just use the complete rear end or upgrade
It's not so hard to change pinion bearing and set up the smear pattern again but...
Its a gamble. Material from one bad bearing could have damaged everything else in there. That versus a hundred dollar bill at most and a road trip of reasonable distance for another would be my conundrum. I would first have a good look at everything in the rear I have. If the wear and oil contamination isn't severe I would place my bet.