I have a '78 Special tank with dual vacuum petcocks. I am switching over to a single non vacuum system, and am wondering how should I go about blocking off the other petcock opening on the tank. I know I could cut a piece of steel plate to block, but am curious how to seal it from fuel leaking out. I have the old stock petcocks and don't plan on re-using. I though of cutting the base of it off and filling the hole with JB weld. I like the idea of the base and utilizing the stock o-ring to seal, but also concerned that the JB weld wouldn't be leak resistant. Anyone have a good suggestion for a good seal?