This has been asked before I am sure. But need to know. I have changed my 318 to a built 360 in a 72 Val. I am getting everything put back in when I looked and saw the holes uner the exhaust ports. The Headers, (TTI)) do not cover them. How can I plug them so they will not leak. A in the car fix would be great, but I can pull it back out if I have to.