What's this rear end worth?

Just switched from a 7.25 to 8.75 rear end as I am installing a built 340 into my 66 barracuda and thought I better upgrade the rest of the drive train. I have never driven the car as I bought it from two guys who tore it apart then realized they were over their heads. The 7.25 rear end is drum to drum, 3.91 sure grip. it came out of my 66 barracuda 273 4 speed car.
It turns freely and the car pushed around in my garage just fine. Just curious what something like that would go for as I no longer need it.