Fuel pump question 1979

[truckin 79]

So I was looking under the truck the day and noticed a random hose by the fuel pump. It is a rubber hose with electrical tape and it is bent in a U shape. I thought well maybe it is a vent hose for gas tank but there is no place for it on fuel pump. The fuel pump just has a line coming from tank and one going to carb. I looked at fuel pumps on Advance auto for a 350 and still no fuel pump with a vent provision. The rubber hose is connected to a steel line but was hard to trace back. Anyone know what the line might be and why it would just be hanging there?