5.8L, 351w, carb. connection?

1978 Ford e150. Standing in front of the engine compartment looking at the carb. behind the dist. One connection, lower right is the fuel line connection. Slightly up and to the left is another similar looking connection. Questions: What is it & where/what does it connect to?

Haynes, Chilton left me still scratching my head. I'm a very minor league shade tree mechanic and after some work can't remember/figure this out.

Thanks in advance for any help. Ken