There are weird intake gaskets on e-bay. There is no divider between the 2 close intake ports. That would seem vacuum leaky. What is up with that?
Those would be 67 intake gaskets, I have pulled down several 67 400/430's with these gaskets. I believe the factory decided that since these engines had a dip between the comon wall between the 2 intake ports, (which basically all the big port heads had this depression), there was no need to try to seal it with a gasket. It will cause no vacuum leak , it could however cause some leakage from port to port, probably would not be an issue as far as how the engine runs. Jim Burek