The 1 ton frame has many differences which would be the thickness of the metal itself, the height of the rail, and the width of the rail. I do have the spec info at home. the 1 ton does not have the hump in the back over the rear axle. If you are interested I have a 3805 1 Ton frame from a 57 Chevy Panel.

1957 3805 Panel
It's not how you fall down, but how you get back up.