RE: New Hangar 9 1.50 P-51 Build
The hex part of the muffler header does NOT touch the exhaust port when tightened down and still has at least 3-4 threads still visible.
The ball link assembly did have a washer on it where you mentioned. It all just vibrated loose and fell out. If this happens again.....I'll put a nylon lock nut on the bottom side(if they make em that small)