My uncle did a 1948 1/2 ton on a 73 Blazer K5 chassis. It required a frame stretch and significant extensions to the body mounts, IE the body was raised WAY OFF the frame. It was a 4x4 conversion with 33" mudder tires (which rubbed sometimes). The frame had the stock suspension on it. I seem to remember the bed was lifted off the frame about 8-10 inches and something similar for the cab at all mounting points. It required a significant amount of fabricating experience, but looked/drove very well after completion. I believe he cut out the lower section of the radiator core support and welded in a U shaped piece of heavy metal which which allowed a custom adjustment.
