Holy Barbells Batman! I really hope you found a defective scale. For reference, I don't have an actual empty weight, from a scale, for our 31-ft non-slide Jayco on E450. The label in a cabinet says something like 11,200. We pack awful heavy, and need to cut down, but we scale FULL (two of us plus too-much-stuff) at around 13,500.
Previous posts are right that you probably cannot fix it to legal. I'm covered up in stuff to do for awhile today. If you want to PM you phone number, I'll can call you later.
I'd like to know what the Wheelbase is. Ford probably provided a 158" chassis then Damon had somebody stretch it (ours stretched 60" to 218") and add a rear overhang extension as well. Damon's label, and maybe one from the stretcher, should have the extended length.
For those of you watching at home, this is why Ford brought out the E-Super Duty, which they shortly decided to call E450.
I've been saying lately, that a shopper should include a truck stop CAT Scale visit in their test drive. Dittmer would probably join the chorus. Ron, you know we'll be called by the derogatory term...
Weight Police...