Then they used a custom fabricated extension tube to extend the filler neck and vent tube up to the top of the fender. Danko makes one for the wide body kit but they don't sell it separately.
You can make your own but it requires a bunch of custom fabrication to make it work. Then you have to seal off the side fuel door and repaint the quarter panel. The one posted cheated a little by using a large side panel decal to cover the body work on the old fuel door.
It would actually be easier to modify the side door and replace it with the Chally fuel door...but you will still need to rework the opening and repaint the quarter panel. You just won't have to modify the fuel filler neck and vent tube.