I did not sweat it when I put my 71 back together. The front end is bolted to the radiator support basically, and that has the same large holes and lots of slack to work with.
Here was a snag: my car was sitting on jack stands, stands placed behind the front wheels where the frame widens. Full 454 and front suspension installed. The weight of the front flexed the frame down so I had to shim the hell out of the radiator support to get the fenders and door to line up. Damndest thing since the same fenders came off the car and the doors were not removed. Let it down and the frame straitened out, now the panels did not fit again. By that time I realized I had perfected the long way around back to square one.... undo everything and reset and reshim the radiator, inner fender wells, front fender.... Good luck. Mark
