[Spits] New tank - slight hitch

[s1500 at comcast.net]

With some elbow grease, I got the new fuel tank in, but with one hitch. Always a hitch with new parts. 

The Fuel filler cap doesn't fit on quite right. At best, it sticks out a third of an inch from where it should be. It seems the fuel filler neck on the tank is a bit far forward. Did my best to fit things together so as to no fuel leaks when I fill-up, but I think I can do better. I'm not sure if the neck is exactly advanced forward a bit too far, or at some weird angle where the back of the neck area isn't giving the filler cap enough room. Tried loosening the top bolts to change the angle a bit, to no avail. 

In theory, could one put some washers as shims to overall move the tank back a bit to line things up right? That's gonna be fun on some of the hard-to-reach zones between tank & car for bolt holes.