The fan pulley is a cadmium finished assembly whose belt connects the water pump to the fan blade. It is the same on all cars, no matter the engine or body style.
The pulley is in two pieces A90411 pulley and A90386 adjusting pulley. These pieces nest together and have three angled slots. When the fasteners are loose and the pulleys are rotated it adjusts how the belt fits. Being fully open the belt will ride towards the bottom and fully shut it will ride toward the top of the V of the pulley. This is the method used to adjust the fan belt tension.
Three special carriage bolts SZ9405 1/4 x 28 x 9/16 fit into the slots from the inside through square holes.
On the outside are three special washers WZ9114 with a tang that fits into the angled slot.
WA4 lock washers and NA4 nuts secure the bolt and washer when the belt is adjusted.
Completely disassemble the pulley by removing all the fasteners. Clean and sand the mating surfaces of the pulley so they slide smoothly together. A little light grease is advised. Clean up and weld the factory holes back to a round shape if they have been pounded on and distorted.