[AnthonyG]

Heads don’t show any evidence of additional machining on either side of spark plug threaded holes. Light spot-faces on outside of head where plugs wire connect end is. No chamfer or counter bore on inside, threads enter as-cast chamber area. Guess it could be a different model design? I had an 8BA built by Jerry Livingston, owner of United Engine Specialists in Wichita Ka. Only marking on the head is the Offenhauser cast in & a 400 stamped on top side near temp gauge threaded hole see in pic.