If it's spilling out on the outside, what's stopping it from spilling over on the inside which is lethal in my opinion. It must be the way you're pumping gas, unless your state doesn't allow the customer to pump gas, and some miscreant is doing it. Then for sure I wouldn't risk that. Most of the time those who pump gas for you just lock in the clip and let it fill on it's own until it burps out. Cutting out the present fill hole and relocating it is going to be expensive. Not sure you've thought it through.