carb vacuum ports

[scroller bill]

Hi all. question 4. Vehicle info in my signature.

On my 4brl carb, looking from front of vehicle, there is an open port on top front and a pluged port at bottom front corner. (pic below) Where does the open port go and where does the pluged port go? There are no other open or pluged ports on the carb. But I do see what looks to me like a jumper hose from one port to another on the carb, is this normal?

 

[Seabronc]

Again the picture is hard to see but the top one is the EGR port and the bottom one is the S port. That looks like a Holley 4160 carb which is the same as I have, picture attached. The vacuum diagram attached is for a 351 with a 4180 which is similar to the 4160. the two carbs are similar but the 4160 doesn't have bowl vents.

Yes, that hose is required to prevent the automatic choke from overheating. In some carbs it is internal but they didn't have room inside the carb on the 4160 to do it so they made the connection externally.