I have a 84" CJ7 258 engine. I noticed my stock (plastic) valve cover was leaking oil. I decided to not only replace the gasket but to also upgrade the valve cover to an aluminum one. First off, I didn't know you had to tap the already unthreaded 2 wholes for the new valve cover to be installed. I don't know how to do that, so I decided to use the stock plastic one again. After installing the new cork gasket using a little RTV, it's leaking. What's the best way to secure a valve cover... Valve cover gasket?