Interesting. Hayden's online catalog only lists the 73 and newer Imperials. It happens to be the same as the New Yorkers. The part is suggests is 2706.
The difference between the 2705 and 2706 clutches are the depth of the stand off from the water pump pulley to the mounting surface of the fan blade. The 2705 is 1.53" and the 2706 is 1.75" deep. That makes the total height of the clutch go from 3.11" to 3.30 inches.
I think I can live with that.
Now I need to see what the shop says about the radiator. It was clean on the outside but full of rust on the inside.

We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon