If its a muscle era MOPAR, the fan clutch is available from MP along with a 5 blade "low drag" fan. Link below. I use the MP setup to help cool a 496 BB with good results. Hayden may have aftermarket versions (NAPA). I've used their stuff in other applications with good results. Autozone may sell a "torqflow" brand. I avoid that one after a bad experience on a DD Durango.

http://chucker54.stores.yahoo.net/vifanpa.html