I know the rubber Valve cover Gasket still comes in the Felpro rebuild kits(gasket set) And to the Best that I know It is Still available as a stand alone. And My Valve cover is taller then the Marine covers So I don't think it would help you anyway.Because of your air cleaner.

Larry/Twisted6
[oooooo] smile
Adding CFM adds boost smile
shocked God doesn't like ugly.