Rear bumper

I don't think that much of a gap is correct. Have you tried adjusting with the brackets? Also, can you weld? It is fairly easy to take up slack like this in bumpers by cutting , adjusting and welding on the bumper brackets. The gap on my rear 69 Cuda bumper was pretty bad, and I cut about an inch from all brackets. Once I welded them up and powder coated them, they looked great, and the bumper fits great. You can do it.