TH-400 BOP short tail $300 in PA/Philly

[newtownhood]

Fully rebuilt trans with an issue...500miles behind a 455 powered pro-touring car. I told the trans shop to install hardened sprag, they said I didn't need it for 500hp...It broke. Trans feels like it's stuck between 2nd and 3rd gears. Drives, does not slip. If you're a trans dude, it's a few hours work and $80 part to fix. This is BOP (buick,olds,pontiac) ONLY case which is hard to find now. Sitting in my garage. Car is gone, on to new projects. Paid $1k to rebuild on top of the $300 used trans I bought. No convertor included, I reused it in the next trans I installed. I'd like to get $300 cash

came out of a '77 Pontiac Grand Prix.