Gas tank vents

[70BEE&500]

Need some help before my car burns down. '70 Coronet 500, 2 vent ports on tank, no return line. Which vent port goes to which vent line? My tank has a short tube inside and a long tube inside. I have two external vent tubes, one to the shock mount and the other goes up into the trunk and back down. Which way should they be connected? The way I have them now, with a full tank and hot days, the tank pukes out fuel from the shock mount area and it is a fire issue. My exhaust dumps are right there and they are HOT! I thought about just switching the vent lines but with the full tank, I may have fuel all over the place. Guess I could siphon the gas AGAIN. I just want to understand why the vent lines are the way they are. I know they provide room for expansion/contraction and vacuum breaking for fuel delivery.
Thanks for any help as I don't want my girl to burn down.

 

[1badstroker]

Your car is by chance not from California in 1970 is it? They had some funky system that they call a thermal expansion volume tank that uses a special cap so it does not puke fuel all over the place on 383 and 440 single 4 bbl carb only.. The cap has a two way relief valve. I can't find a diagram of the system to show that system. I only find it in writing with no pictures.