For all intents and purposes, they are the same machine, and you would be happy with either. Have a 79 CS_Special,ran 12 years and have spent less than 1 grand on repairs over 1500 hours. Easy on fuel(diesels--4cyl turbo) easy to repair and used parts are plentiful since many early F parts will fit. Heads are easy to locate, except for series 3 Flex heads, and yours can be upgraded to accept a series 3 head. Can be hard to start in cold weather, and the cabs are prone to mice if not kept scrupulosly clean, leading to damage to the monitor system and cab insulation, but all machines suffer this with poor housekeeping. Ben.