Naa, your looking at it wrong.
Start with the Hemi Dodge 4x4 chassis of your choice. A standard cab version would be best if you could find one. The WC cab is a standard 39-47 Dodge truck cab (all trucks used the came cab, but the COE had some different front sheetmetal .After the cab, you just need a bunch of 18 gauge sheet metal, a way to cut it, and a metal break and roller. The box was flat sided with an angle at the top, and square tubing for stake pockets. The fenders are flat metal, the front with a few bends, the rear bent into a curve. All the spacers between the fenders and running boards are flat pieces that bolt or screw to the body and fenders or running boards.The most difficult would be the hood, and I believe you can still find them, and may be able to buy repops from www.vintagepowerwagons.com.
It will be easier to build the truck over top of the chassis then to try to add the Hemi parts to the old power wagon chassis.
One more thing, those 39-47 cabs are pretty small, you might want to be sure you can fit in it before you build one. I learned that from experience. Gene