Assuming all the hard parts are serviceable, Mancini used to sell a race rebuild kit with the good clutches and steels, all the seals etc shift kit and a deep pan for about $300.

I dropped my core off with that kit to my trans guy and he charged me $300 cash to build it. That was a while ago so I'd expect it to be a little more now but should still be no more than $800ish.

Shouldn't take more than 3 or 4 hours tops to clean and build it.

Kevin