Do these exist?

mvh is correct. I have a 1967 Barracuda, and so I bought the 1967 service manual. If you look under Cooling, then Specifications, they list fan info for all the car models: diameter, number of blades, type of drive (solid or thermal) and more. The 273 with A/C and the Clean Air Package is the only engine listed with a 17" clutch fan, at least in 1967.