Yup, its common, and it bothers me, too. But the gas tank can be shifted sideways about an inch, by loosening the hold-down strap and prying it over, then re-tightening. This is best done with a very low fuel level- gas weighs nearly 7 lbs per gallon- a full tank will be 150 lbs heavier than an empty one and proportionately harder to shift. And don't be afraid to bend the tank in with a bar between the header and shield- I had to dent my shied & tank an inch or so when I added SVO heads, which have 2-1/2" higher exhaust ports than stock. Do NOT pry on the tank itself- you can cause a stress riser that can crack later, leading to all sorts of unhappiness. Pry between the pipe and shield and don't overdo it. But I'd try unbolting & shifting the tank first.
