I have always used to Fel-Pro Neoprane Gaskets.
It is basicly a metal shim that has rubber "ribs" on it. I forget how much they were, and the part number (I apologize for not having that info)
The valve covers came in a slightly Transparent packege and it consisted of a silver metal with Blue colored "ribs" that make the tight seal.
They seal up well as an alternative to the rubber or cork gaskets some people use.
With the neoprane gaskets...Torque them to 9lbs and forget about them.