I've heard the fan set up from a Taurus SHO will fit, but not sure if it provides the necessary CFM of air flow that the 4.3L engine requires. The temp sensors, relays and wiring are usually available at an auto prats store and not that difficult to wire up and install. It's a lot of work and money for a little, (if any) gain that you might get.
Fan clutches are not all that expensive, they've been around for years, and work very well.