Hi
I received my new rebuild carb from RockAuto yesterday. However, there is a slight difference compared to the one I had before. At the bottom right side there is an extra small tube for a small hose. As you can see from the pic (left side is the new one, right side is the old one) I did not have this option before, so now I don't know where to attach the end of the hose coming from the carb. Hope someone can help, thanks

 

Depending on the year, some engines had a vacuum advance on the dist . that was controlled by a vacuum hose from the port you are questioning.
If your engine doesn't have a vacuum advance on the dist., just put a screw into a small piece of hose and block the port.