Agree with John. Scrap iron prices are up and that's the easy button. The only interest in my neck of the woods for Eaton 4.56 or 5.13 gears are folks with rock crawlers or mud trucks. If there's a shop in your area that specializes in either, they may pay a reasonable price for the differential.
1951 3600 with Clark flatbed, T5, 4.10 rear 1970 340 Duster 1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain) 1951 Farmall Super A