Most 216 valve cover gaskets that are available these days are slightly too short to seal properly. Cork gaskets in particular have a tendency to shrink, and other than soaking them in very hot water prior to installation, there's not a lot that can be done to improve the situation. The fix is fairly simple- - - -and it doesn't involve using any of the common squeeze-tube gasket material. Buy two gaskets, and cut them on a diagonal in such a way that when the remaining pieces are patched together, the total length is about 1/2"-3/4" longer than original. Glue the gasket pieces to the cylinder head with 3M trim cement, paying particular attention that the diagonal cuts are joined firmly and evenly. Then bolt the cover down, and don't overdo it on torque- - - - -firmly snug should be plenty. There should be about 1/4" of gasket protruding past the metal all the way around the valve cover.
Jerry
