Your 80532 would be a 1250 Dominator. I also happen to have one I converted to a 2 circuit carb. The gasket you need is the same for most 3 circuit Dominators, any speed shop should have one. If you have to order any Holley parts you can get everything you might need here.
www.blp.com
800-624-1358
Ask for Joe, Mark, or Robbie on the counter.