I am doing a similar project with 1950 1 Ton C&C Dually. Was a hydraulic lift flatbed/stake bed farm truck but I've since discarded the stake bed sides (horrible condition) and removed the wood decking from the remaining flatbed. I just removed the entire hydraulic lift this past week (sitting on trailer in pic) and am now in the process of locating a gas tank to mount between bed rails...I'm looking to do an LS swap in the future, so the gas tank will also be replaced at that time unless I go with a current fuel injected tank/pump combo and add a fuel pressure regulator for the current 6 cyl engine. I plan on disc brakes all the way around but I intend to keep the front and rear suspensions. Interior will be mild custom and body will remain as is for rat rod appeal. I like the GMC truck as you don't see many...compared to the Chevy's. Good luck on your project !
'50 GMC 1 Ton Dually - Barn Find (sort of...no barn)