So from your avatar RedRam, I presume you have a 70 Dart, like me. I believe that 67-9 Darts have a set up where the flange goes on the outside of the body, as opposed to a 70 where the flange is inside the trunk. The reason for the change is the nipple for the vent tube on a 70 which makes it impossible to insert the filler tube from outside the car. For ours you push the tube into the tank to get clearance to get it past the trunk opening.