Charlie, I tried to PM you, but for some reason I can't get it too go through. Take your camera when you go to pull-a-part and if the truck has any decent sheet metal let me know. In regard to the pulley, I have several truck pulleys, but I have never seen one that looks like yours, unless it is two pulleys stacked together. If it is just the single grove inner pulley that you need, I just pulled one this morning.
After looking at the picture again, I have never seen one like this, I don't think its from a Y Block unless it came from an aftermarket A/C kit.
Glen Henderson
Freedom is not Free
Letohatchee, AL