70 charger fuel neck vent tube

[mopar70charger]

i have a 70 charger with all new gas tank everything basically and dont have no vent lines on tank but there is a vent tube on the fuel filler neck can someone tell me exactly how this is installed and or whats needed..i do have the tube with a rubber hose on one end about 5 inches long ..also is a  vapor canister required i dont think so but would like to be sure..thanks

[Domino]

it goes through the trunk pan with a grommet into the hollow frame rail below. 

[mopar70charger]

so your sayin the tube is attached going thru the grommet which is then goin thru the trunk pan were it should pass in  the rear frame rail on drivers side and not just thru the trunk pan anywere, just so i understand this correctly..thanks

[Domino]

right.   On mine, it's a metal line that goes through the trunk pan and is open to the air inside the frame rail. 

My guess, vent and maybe an overflow tube, but mostly a vent that is located high enough that fuel can't slosh out of it.  With the flip cap sealed and tank to neck sealed, air is in drawn in through this tube to replace the volume of fuel that is used by the engine.  Maybe if the neck fills up with fuel at the gas station, it might give it a place to run out and not down the side of your car and/or on you.   

[b5blue]

I agree about the vent, the vapor separator requires the return line fitting on the senders disk. Probably not "necessary" as I ran my 70 for years without it, (cap on the return nipple) but after the engine rebuild I added it just to be safe. (It gets really hot down here in Florida.)