rock auto dot com is your friend.they list a fan clutch for a 71 350 chevelle. Real easy and reliable site to deal with for parts.I have a Radiator fan part #3989095 approx 19 inches dia.
I can't find the correct fan clutch. I called Hayden, OPG, Year One and even Delco
The Part is original to my car which is a 71 Chevelle Malibu with a 350