Any ides on what this is worth?

Atlantic Speed sells theirs on FleaBay for $349.99

http://www.atlanticspeed.com/productcart/pc/viewPrd.asp?idproduct=7693

You could use that as a starting point, since Edelbrock still makes them, I don't know if they're worth a big premium over the new ones.

Nice survivor looks to be in great shape!!!