Ken, my apologies for not responding. I have not been on the forum much lately, and just wasn't paying attention! I don't have a tri-power, so I can't answer your question.

Hi my name is Ken and I am restoring a 66 GTO 389, tri-power, four speed. I am a backyard mechanic and have a question on the intake manifold. It has a recessed 1 1/8" dia. hole water passage through the timing case cover. In the new gasket kit there is a 1 1/16'' O.D. X 1/2" center hole. This is a very sloppy fit. The last person who replaced this seal used blue permatex encaseing the seal which was off center and he used a knife to trim the I.D. Parts houses have no answer for this. Do you know the correct leak free installation? If this is a larger seal where can I get one? Thanks for any help, Ken