clutch fan vs standard fan

For a typical sub 450hp streeter
the thermostatic clutch on an all steel 7-blade fan will do a great job. You might never even know it's there.
My 195 hi-flo coolant thermostat keeps the minimum water temp at about 205*F, and the clutch together with the hi-flo pump never lets it get past about 207*F, what a team.
This fan works hard in traffic but once past about 35 mph, ram-air thru the rad decouples it, and it freewheels. So at rpm, in Second-Over/ 93 mph it is just along for the ride. On the return road, while the Alloy heads are aircooling, I hear the clutch start-up again. But the gauge hardly moves.

See; that is the One aspect the Dyno never tells you. Once the engine is installed in a moving car, all those dyno-test results go right out the window. Well except the direct drive one, but I don't know anyone who would, other than for testing, run a direct drive fan. I mean imagine the tip speed at 7200,lol. That's crazy.