Found what I think is a Aisin black hub fan clutch today. Was in a salvage yard walking by a stripped 80 with no engine but there was a fan clutch/fan assembly just lying out in the open. Picked it up and saw the black paint on the hub. No oil stains from leaks and it spins smoothly with resistance so maybe it's still good??
. I have the original Eaton clutch that came with the truck which seems to work OK, never overheated but I don't have a scan gauge or temp gauge mod so don't know what the temps are really doing.