Wrong. The original tank slants upward from about halfway back or more, so the end is behind the impact bar of the unibody (the part that the bumper bolts to). That tank on there now was originally protected by the big bumpers & impact bars that the '74-77 models have. So like I said, 'hope you never get rear-ended. It's not a safe setup. That valance won't stop anything.
My Comet has zero problems during fillups. Probably because it doesn't run yet so I never need to fill it up. But it's not model specific either and many old Fords suffered this same fate and I can fondly remember trying to find that "sweet spot" to speed the fillups. BTW, your car looks awesome! Can you post a few pic's of it in your garage or media gallery?