If and when you remove the heavy steel firetruck rear section and the pumping equipment from the front, you will find a huge weight savings. My '57 2 ton with a cab high 15 foot wood grain box weighs 7400 lbs empty.
Oh yeah, that body probaby weighs a ton. Not only will that weighht reduction mean I can haul more load, but I believe it will also allow me to get the truck back to the original total weight rating as I'll be able to distribute the weight more freely along an open flat bed. Makes sense to me at least, as long as I don't exceed the weight rating on the rear axle I don't see why our inspection agency would have issues with re-rating it for its full capacity.