looking at a 57 i just bought and saw a ram horn manifold, on the right side, that looks strange to me. where the choke tube goes in there is a raised hexigon area. behind that, above #6 cylender,there is a bolt that looks like a plug.these are parts of the casting not added on. have never seen this before. any ideas. i do not know how to post a photo. e mail and i will send one to you. maybe you can post it for me. thank you