Fuel Tank Venting Question

run it out anywhere under the car towards the rear.

The 69's loop it up and then back down and under the car right near the filler neck.

??? Misleading, and it will likely siphon

The line coming from the tank area clear up to the front of the engine bay----and which originally interconnected with the carbon can system IS YOUR vent on any car with the evap system, and that means some 70, some or all 71, and all after that. They used a "pressure vacuum" filler cap to relieve pressure "in case."

If you have the 1/4 "up front" line intact, it needs to be "up high" in the engine bay to prevent siphoning. You can hook it to a filter, and or plumb it to the air filter bonnet, or even just leave it open. May have a few "fumes" in a garage

What I would lean towards if you are modifying the system is to construct a replica of the 69/ earlier vent, which is a 1/4" line teed into the filler neck up high in the trunk. Goes up, clear up to the top of the rear quarter panel, then loops down alongside the filler and ends (open) below the grommet. This prevents siphoning