I don't understand why you need to change anything so far as vent, some caveats:
If you have the "carbon can" setup the tube coming up front IS THE tank vent. You don't want to remove that, or if you do, make other allowances. You can run it "up high" in the engine bay to prevent spill over, and even plumb the end to the air filter bonnet to prevent "smell."
Otherwise, I'd replicate the 69/ earlier vent, which is a nipple welded into the filler neck "up high" in the trunk, with a vent tube run way up against the quarter "roof" and then down along the filler tube, pointing down and open into the cavity in the frame rail below the trunk. Oh, a non vented cap.
I believe your car ?? had the separator can in the trunk??
Go to MyMopar download the 70, 71, 72 service manuals to get an idea of what they did, in the fuel section, and in the back, emissions section
Then get anything before 70 and look up how it was done
Earlier venting:
View attachment 1715126910
