back for more help..fuel system

[baboiler]

1980 gmc 4x4 350ci . All the fuel lines and setup look original. I am not getting gas to carb. Thought it was bad fuel pump. Put in a new one - no gas at carb. It is dual tank. Have never used passenger side tank.Had never touched the tank selector switch until today.After crawling around under the truck I realized I have no idea how this system works. The switch valve appears ok looking at it. Lines not dry rotted - no wet lines to be seen.I don't hear any clicking noise when I flip the switch.I have no reason to believe this is the problem but after confusing myself looking at the setup I'm not sure where to look next.The only fuel filter I can find is at the carb.I unhooked the gas line before that filter and can not get gas to there.Was hoping for a plugged filter but don't think that is it.Truck just died on me. Have been driving it daily with no problem.If I drop some gas in the carb it fires right up.I really don't need a second tank. Can I simplify this for me by converting over to running off one tank?Big job?Any advise greatly appreciated. Need to get it going. It's my work ride.Don't want to have it towed and fixed if it's something I can do.