Good used core grade OEM Ford or Mercury viscous fan clutch as found on mid-sized Ford cars with 289 V8 engine and integral air conditioning. B and C bodied cars, 1966 and 1967 Fairlane, Comet, Montego, and several variants like Ranchero. Overall length is 3-5/8 inches long, and fits fans with a 2-5/16" hub. I am unable to turn the hub, so I am calling this a core fan clutch. Perfect cosmetic condition for restoration. 

There are two Ford fans that I have found that use this clutch. C4OZ-8600-C - 7 Blade aluminum fan with 17-1/2 inch diameter stamped C6OE-C, and C4OZ-8600-D - 7 Blade aluminum fan with 17-1/2 inch diameter and stamped C6OE-G. No fan included, just sharing information.