Canister on the passenger side fender?

This would require dropping the tank and adding a fitting correct?

"Maybe" I haven't done much with the later cars. The ones that had the trunk vapor separator, you could "tap into" that. But the later cars had "that function" in the tank, with only one line coming out. If you could drop the tank and pull out the filler tube, you could duplicate the 69/ earlier vent which was simple.....Just a 1/4" tap high up on the filler tube, bent up high to top of quarter panel, then run down, through the seal, and end inside the frame rail

If you don't want to yank that all out, and IF you don't mind a clamped connection in your trunk, you could use a tube cutter and cut the filler tube in the trunk.

On my 67 I did this: Drained the tank, and plumbed my MIG CO2 tank and regulator to the supply tube, let it flow until gas fumes were forced out the top. I verified this by putting a tube on the factory vent, and "could not light" it anymore. Had an extended tube coming off that several feet a way.

Then letting the CO2 continue to flow, I punched, not drilled, a hole in the face of the tank above the axle, and just silver brazed it in place.

YOU CAN ALSO GET an aftermarket sender with two fittings. Use the one for your return, leave the factory 1/4" line for the vent

In any case you need a vent

vent.jpg