Brian I just realized you are working on a 55 year old car that is probably all original. Have you checked out the suspension? Brakes? Driveshaft U-joints? The sub-frame bushings are probably shot. Control arm bushings, ball joints, springs, shocks, tie rods, all important stuff before you take off on a joy ride. Being a 400 car did it come with the front disc brakes? Because 4 wheel power drum brakes is a nightmare. I had a 1968 Buick with 4 wheel power drums. You could put your head though the windshield if you weren't careful.
