I decided to install the stock oil fill tube rubber o ring and metal washer on the inside of the valve cover. Felt real tight and looked like a good seal. I did have to shave the thickness of the gasket with a razor blade, though. Anyway, now I am wondering if the hot oil splashing all over the inside of the valve cover will rapidly degrade the rubber o ring and the little bit of silicon I used? Did I make a mistake? As always thanks for enduring my inane and banal questions.