Gas pours out unused right tank 81 K30

[farmall]

I have been using my left/drivers side tank since I bought this rig a few years ago because when I switched the tank selector switch the gauge did not change.

Recently I have noticed that if I let the truck idle or after a drive or even first thing in the morning there will be up to a quart of gas that comes out the right/pass fuel fill opening/cap.

This 81 K3500 has a 454 with a two line fuel pump with no return line and no sign of a hard return line on the frame rail.

A real head scratcher.

My NAPA is having a friends and family sale next week so I am thinking of getting a new switch and selector valve.

I also have an 87 parts truck with dual tanks but I have not been under either truck with fuel selector on the brain to see if they are the same.

I found this thread to be of great help.
http://67-72chevytrucks.com/vboard/s...d.php?t=567277

I do not know if my selector valve has return ports or if they are capped or open and I cant think of why my right/pass side tank would be filling up.

I would like to get this fixed and don't mind buying the new parts but if my new valve has return ports do I just cap them?

Ideas?

My build thread.http://67-72chevytrucks.com/vboard/s...d.php?t=643974