Which sending unit.

[Senck243]

I have an 84 k10 with a 305. Took the bed and both fuel tanks off to coat the frame, new brake and fuel lines. The saddles were shot so I got used ones but I am only putting one tank back on. I dont need both and its more money I dont have. The oe sending units had 3 outlets so doing a single tank do I need 2 or 3. What are each one for? Thanks

[Captkaos]

Supply, return and Vent.  Getting rid of dual tanks has nothing to do with the sending unit.

[Senck243]

Thanks. Vent just goes out of the tank and stops right?

[firefighter]

Thanks. Vent just goes out of the tank and stops right?

My vent was run (via a rubber fuel line hose) toward the back of the bed with one of those plastic vent caps on it.
That keeps any gas vapors toward the back of the truck and away from occupants.

[Senck243]

Thanks firefighter

[DnStClr]

Actually, if it's done properly, the vent line will run up to the vapor cannister (on the driver's side under the hood.) That's the reason for having the cannister.