I have a 77 gmc 2wd with a 350. I have been restoring this truck over the past year and i am putting the gas tank back in and i have a line that runs from the charcoal canister to the back of the truck (runs with the fuel sending line) and i cant remember where that line goes. Im assuming its just a vent or something. The fuel tank sending unit only has one line coming out of it so it cant go to them fuel tank. Anyone know where that second line hooks up at? Or do i just plug it and forget about it?