Use a rubber valve cover gasket. Clean the mating surface of the valve cover well, there should be tabs on the rubber gasket to insert it onto the cover first, and have it stay there without falling off. Rubber enables you to take the valve cover off and on again without having to replace it each time if you had a cork gasket.
Why not check/adjust your valves while the cover's off? A simple valve adjustment can go a long way for better drive-ability and fuel economy.
Best,
1970Dart198
