'76 D100 83/4 rear end good or bad?

http://www.moparts.org/Tech/Archive/axle/16.html

The housing will be too long.

Actually if the center is a suregrip with 3.55's I think I would grab it just for the center section. Then you can find an empty housing or one with just the axles and such and pop that center section in it.

That's not a bad price for a center section alone with what's in it.