Help with pricing a 8 1/4 rear end

I currently swapped out my 8 1/4 rear end with a 8 3/4 for my 1975 dodge dart swinger. I needed something bigger. Now I am trying to sell the old 8 1/4 rear end. I have a few things that go with it like 3.91 richmond gears and a carrier for the gears. It just needs a rebuild kit and someone could just bolt it right in. What do you guys think I should sell it for?