FB Marketplace is good-ish, and I've sold a lot of Corvair parts on FeeBag. A loyal crowd, but not a big $ crowd. Speed parts and good bucket seats are the big-ticket items, as are options.

If you could find a local Corvair guy and sell the entire lot to him, you'd be far ahead. If you have to join a fb group, one guy with a truck and willing to drive to you is the best way to go.