are 8 3/4 junk now?

A body rear ends aren't that common but they don't go for $2k. I sold one a few months ago with a SG complete with brakes and sbp axles for $500.

Those 8 3/4 rear ends you mention as well as those found in pickups and vans are defininetly worth something. If a person was set up to cut down the housings and could cut down and re-spline raw axles, a guy could make a decent living building rearends, ask Dr. Diff.