Need help with 76 chevy 4x4 LWB Fuel lines

[Robin_Siler]

I have a 76 LWB 4x4 Chevy. I need help figuring out how many fuel/ return/ vapor lines it has. The poor truck has been jerry rigged by the previous owner.
I bought a new fuel tank for the drivers side. When removing the old one there were 2 fuel lines at the sending unit. One line went to the cross over for the passenger tank and the other was blocked off. On the fill tube there was a vent line there that went back to the tank itself. No passenger tank installed but eventually I do want to install it. Help Please

[jsavage977]

well your pictures are really confusing to me lol.
on the sending units the largest tube will be your fuel supply line. the smaller one will be for your venting and return line, if you need a return line.
so you can run the two smaller tubes together to vent the two tanks from side to side.
the easiest way for me to help you is just to show you this link to another forum. examine the diagrams carefully.

http://www.truckforum.org/forums/che...e-routing.html

[Robin_Siler]

I guess I need to know if my truck is required to have a vent line coming back from the engine or if the vent hose on the tank filler neck will cover that? My sending unit only has 2 ports. Thank you