I have always been told the frames on 1956 F-100 (1/2 ton) and F-250 (3/4ton) are identical but the springs on a 250 are heavier and the brakes are bigger. I have my 100's sitting beside my 250 and the frames are identical, except....the frame rails on the 100's is 9 guage (.156) and the frame rails on the 250 are 6 guage (.203). This F-250 was originally a cab chassis and used for hauling grain in the Fort Benton, Montana area. Not a lot of rust, but a lot of dents. I hope I can make an awesome flatbed out of it. I had hoped for a 350 or bigger, but had too much trouble with the widowmaker wheels.