Luray You can take a thick cork gasket and coat it with silicon while new,wash all oil off of the head valve cover gasket rail with any solvent ( Iuse laquer thinner) then glue your gasket to the head. Let it dry overnight then install your valve cover,just tighten enough to stop the leaks.With your gasket coated it becomes a barrier to seeping oil and you can carefully take it off for service.Eventually they all leak I'm sorry to have to tell you !!! I don't think the above works as well with a neoprene gasket if you can still get them .