If the port is blocked off, you probably now have a 009 distributor installed. This port was used with the distributor that had 2 vacuum lines. The crank pully should be marked with a dimple on the outside rim and a V mark at 5 degrees ATDC. To properly time the engine you have to make a mark at 7 degrees BTDC. If you need to know how to do this let me know at cpowell2@charter.net.