Well, found a good used '87, obviously has a newer motor/transmission
(302 MFI and a 5 speed overdrive xmission)

Can't find much in the way of readable data tags anywhere yet.

VIN tag in the door indicates the axle ratio code B9, I believe that
the axles are the original. The rear is huge compared to the one in
the '72 F250 I've had for eleventy million years. Could it be a 1 ton?
Full floating, of course, huge hub, 8 long lug studs like it would
take at least duals. A Ford 10.5? There is a small tag held on by one
of the cover bolts, S127G on the top row, 551023A29 on the bottom row,
numbers don't look like anything I can find in Chiltons. They don't
carry the detail they used to, can't find the tables I need looking on
the internet yet.

Any help out there for me without yanking the HUGE cover off of this
thing and counting gear teeth?

Appreciate any help in advance......