I've mostly used the cork gaskets with no problems.  I use RTV on the valve cover side of then gasket mostly to hold it in place.  Other than that, nothing else.  I have those covers on my 54 and my 56 Bird


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Best Replacement gasket to use on Baby Bird Aluminum valve covers. And best method to make sure they seal properly.