The 8 1/4 thread

I got tripped up, and learned a couple things.there is a 7.25 that looks like a 8.25. Dodge diplomats had them. Give away is the step in the axle tube. It necks down by the diff housing.
2.28 gears had a different carrier.
And the 8-3/8 used in mid 70’s pickups will run 8.25 gearsets.
And all 3 share the same brake backing plates. Drums appear different but all fit.