68 C20 with 327 excessive fan noise

[cjoenny89]

I have a 1968 family owned since new. It is a C20 327 v8 3OTT I have have finally got the truck going after many years. It has a terrible fan noise very loud like you thought the tranny was howling. I took of the fan belt and drove it for a quick drive through the gears and it made such a difference I couldn't believe it. Currently it has the factory fixed blade fan. I am wondering if anyone else has ever noticed this on these trucks? Can I run a clutched fan on the truck?
I would like to know what to order as I know that the fan has to sit in the radiator fan shroud correctly so it draws the correct amount of air.
any suggestions on what to try?