Quote: The one on my '70 Challenger is a grommet with a large tube, similar to fuel fill.
Possibly an emissions deal...ECS?
We have a '70 Barracuda that originally had the large vent tube in the trunk that was about the same diameter as a fuel fill. It had 4 smaller lines at the very bottom that ran to the gas tank and/or fuel return.
I replaced the whole nine yards with the standard fuel tank and vent assembly.