Now that I have the heater box back in place, I am ready to reassemble all that I took apart. I removed the export brace and valve covers to have easier access to the heater hoses and blower motor attachment bolts. I ordered valve cover gaskets from one of our well known suppliers and received the FelPro rubber gaskets. These gaskets are very hard rubber. There is about a 1/8" riser notch that separates the upper and lower halves of the valve tray cast into the heads. The old gaskets were cork. I just don't believe the rubber gaskets will conform to that change in elevation and make a good seal. The previous gaskets were cork. Anyone have experience with the rubber vs cork valve cover gaskets for these engines? As always, thanks for any suggestions.