The Stovebolt Site Forums The Shop Area Engine Shop Exhaust Manifold Flapper

In Michigan? Can't predict motor/carb behavior. Up to you but.........

You have not worked on it long enough. Penetrating oil, a lot. Work just 2 degrees of rotation at a time and axially also. Gradually it will rotate. Emery cloth the shaft near the holes. Vibrate the shaft with an air chisel bump shaft, on LOW air pressure to seep P-oil into holes and break rust particles loose when shaft is both ways vertical. This is a patience only job, no forcing. I see you have sandblasted maybe.