There is a local fellow that has converted several 46-59 chevys to 4wd.ON one 53 model he welded the running gear from a mid 70s blazer to the original frame. On a 59 apache wide bed he set it on a mid 70s truck frame. He told me to weld the original body to the new frame. They all look great. He recomended putting the body on the later frame as opposed to putting the running gear on the old frame. Considering the same on a 57 short bed.