47-55.1 Hey you all, how the heck you doing? I'm working on my truck again!!!

[dsraven]

if you find it burps back when filling you could fab up an elbow riser extension pretty easily that would seal against the filler neck in place and could be used like a no spill funnel, stored in the filler area behind the door. sometimes things just work out that way but it's not the end of the world. I would put the filler and door as high as possible and then deal with the aftermath unless you want to cut the box floor and fab a part to cover the "inside the box" part to make it higher.
it's gonna be a one of a kind. it'll be great to see it finished with a side view that shows the whole area better