[Enoch]

If you look on the flange where it bolts to the water pump sometimes there is a date stamp like "66 D". I have seen this clutch and fan set-up on mid-year corvettes. The flat bar set-up was interchanged with the coil type clutch.
How is the clutch does it have any resistance left?
Your guess is right I've worked on original 64-67 small block cars with this set up.
Oh by the way the fan is correct too. Repro fan goes for 100-200 and they don't repro the flat blade clutch so if it's good I would say it's worth at least as much as the repro coil type cluth which goes for 175.

Hope this helps, Rich.