Viscous fan package?

They really aren't THAT hard to find. If you have some GOOD yards around you, you should be able to find one. They were used on almost everything from the late 70s through the late 80s. The fan is the important part. You can get the clutch units new.

this the fan?

MOPAR 5 BLADE 18" RADIATOR FAN 4140063 NOS | eBay