That is a disc brake master cylinder which was used on most Mopars from '71 through '75. It was sort of a one size fits all, so it was found on a lot of A, B, C and E body cars.
Clean examples are not all that easy to find, but not too difficult either. Sadly, IMO it's too good to throw away but difficult to find a buyer for and a core is probably not going to bring more than $10 or $20 if you can find a buyer.
If the bore is nice and not pitted, you might want to clean up the MC, rebuild it as kits are still available, and sell it as a rebuilt in which case it should bring $50-$75 pretty easily.
