The last couple of years I been having trouble with my valve cover gasket leaking pretty bad. I have replaced it a few times and new grommets as well but it never helped or got worse.
I blamed it on weak piston ring seal (blow by) and I dont run the stock intake system so there is no negative pressure on the valve cover. I had this set like this for at least 20 years or more.
I went ahead a redid it again last week and I notice the new gasket is .100" thinker along the pan rails then the old one..and to boot it fits on the valve cover perfect. I distinctly remember he last two seemed to long and didnt just drop into the grove like this one did. Problem is this one was purchased about 10 years ago I think.
I put the video up.
I think what really kicks me is I knew there was something weird because the original gasket was probably on there 18 years and I used to take the cover off and lash my valves at least once a year.