I've replaced the back valve cover and grommets with a new Fel Pro setup. I can say for sure that the old setup was leaking - the old gasket was not sealing The gasket sealing surface was flat and compressed and didn't project onto the head surface like the new round one does. I venture to say that the new gasket is about 3/32" taller than the old one - the old one was more or less flush with the valve cover and the new one sticks out as it should (to seal against the head).
I'm going to replace the front valve cover gasket tomorrow - after the back one, this will be a piece of cake. Plus, I know that the front one isn't leaking (but I will replace it anyway).
Now that I see the setup I can also say that replacing the gasket without the grommets is worthless. The grommets provide the sealing force (they act a springs more or less that presses the gasket against the head). Without new grommets, the new gasket will be much less effective.
I don't know if the oil pan is or was leaking. But I know the valve cover was.
Thanks for the help guys!
