The long box is a thicker cross section frame than the short box version, it is the same thickness used on the 3/4 ton as well.
Maybe even the 1 ton not sure there.
Just remember what the "TOTAL FACTORY STOCK" Cameo went for at auction with a bent roof for 140,000. I think people that are looking for these trucks are sick and tired of the modified junk out there. Box it and ruin it forever. If you need a boxed frame get some tube material and build a frame, just as much work as boxing the original.
