I don't know what kind of setup the A-bodies use but my Challenger has a vapor separator right infront of the gas tank. There are four vent lines coming out of the tank that go into the separator...then one line from the separator to the canister. You can remove the canister, but you still need to have a tank vent.

If you run a different vent line up higher then the gas tank, you could use your existing vent line as a return if it's a large enough diameter.