71 Duster Fuel vent

Well I haven't made any headway in this issue yet.

I have a cap like the one on the left but still had to drill a hole to make it vent.

My filler neck is a plain jane old tube with nothing comeing off it.

The tank has no multi nipples etc except one single tube that is capped just above the sending unit.


Not sure what I should be looking to do here. Run a hose up off the vent above the sender to a higher point under the car if possible? Look for a better cap or a different filler tube?