just finished rebuilding my 455 for 67 bird now i have run into a problem we put the 6x heads on the 455 and the gaskets dont cover a port in the middle of the head above the normal port. so for some reason there seems to be an extra port. what this port does is beond me does not seem to go any where. stuck a wire down it and blew air into it to find out where it goes with no luck.. Any ideas?