John, your correct about finding rust free iron in the rust belt. Jim, geogrpahics has everything to do with rust. If you have a native, it's more luck than the way in which it was taken car of. How it was manafactured may play a role too.

I was old enough remember--and old muscle was an interest--when the cars stormed the streets with new car warranties. Lots of the cars, especially the fg f-bodies, started showing extensive rust within a couple of years. The rust originated in the sealed areas and rusted from the inside out. Garage kept cars exibited the same problem. Any of the 50+ folks, living in the rust belts, who have kept a lifelong eye on fisher bodies can attest to this fact.

Unless it was a case of how it was manafactured--the plant and the varying quality of work from individguals on the line--something that could be a major factor, the climate, not care of the car, played the main role in the level of rust.