63 Valiant vs 64-66 Fuel tanks

I just put a Tanks Inc tank (same for '63 up) and a DMT grommet (OEM quality material) in the wife's '63 Dart. It does fit a but wonky and this thread now explains it! I am having a bit of a time getting the seal on the trunk floor slid back far enough to fit the factory holes.... It may be because the original '63 was just a tiny bit different. I will drill new holes to align the seal nicely with the new tank now that I know why things are not _quite_ lining up...