The vacuum port you circled was used for a performance indicator in the instrument panel. If you dont have that indicator/gauge just put a rubber/silicone cap on the port.
If you are wondering why a vacuum gauge was called a performance indicator, vacuum gauge readings - Bing
I do have the performance gauge but it was hooked up directly to the carburetor. It never did work right but I also tried this port. It has to clogged, I’ll take this fitting out and clean it up. Thanks man
