1/2 ton truck -1500 series probably does not have enough braking power to handle the loads that adding a dump body to it would bring. You can beef up the springs, but the transmission,steering, and other components will be stressed. Check out maybe getting a dump trailer, they usually have self contained brakes. Maybe add a tow pack to your truck transmission and go with a trailer?
i agree with DADA,, plus i'll add a few things.......on your 1500...
a 4 yard chip box is a little smaller than 4x4x8 (128 cubic feet) ( 4 yards is 108 c/ft ) just dumping chips in the bed,,a full size pickup will hold 3-4 yards...
a yard of chips goes around 500 pounds , , add the weight of the chip box,, and the lift.... you 're way over weight..
plus,,,your tires ,, rear axle bearings and axles,, front end,, and all the stuff DADA said,,, the truck aint made to do all that....stuffs gonna break (someone could get hurt) and if your thinking about pulling a chipper....
i'd rethink this one,, because nothing good could come out of it.. IMO