You can see the filler neck on the bottom photo. I'm guessing you have to cut the stock neck and use some hose and worm clamps. Or maybe the cap screws on there and you have to reach in through the license pocket to unscrew it?
Brian should post the pics of the Stainless Steel tanks I sent him awhile back. Not exactly aluminum cheap but way more sexy looking IMO.
Anybody using the in tank style Aeromotive pump? If I was building tanks this would be part of the package.