I'd tried a solid 6 blade fan like that and it roared like a lion at 3000 rpm. Those are usually reserved for fluid clutch drives. I still have a fluid clutch and solid fan set in the barn that came of my 57 Mercury. I use a 6 bladed flex fan on my 56 Fairlane. It runs quite no matter the rpm and doesn't steal power at high rpm either. 

Jerome  

years with no problems. It doesn't see much high speed use, so I

haven't noticed any excessive noise. Worth a try.

Noise wasn't a problem on my bird until I put the smaller "speed up" pulley on there (to make the waterpump run faster). Many vehicles just don't have the room needed for a fan clutch - but the birds do and that turned down the noise.

This is a GM version from a '70's pontiac - with seven blades. Has the open center for a clutch - which then adds more weight. But the real point is, that the bearings are plenty big enough so long as they remain uncontaminated by water and slightly lubricated. The really big loads on the pump bearing comes from the belt or belts. The second big killer of the bearings is a bent blade that induces a higher speed vibration at many more cycles per second than the rotary RPM.

If you want to use a clutch type unit - it takes some room. T-birds have enough, but many of our outfits do not. This is the Hayden "Extreme Duty" P/N 2797 (5/8 shaft). There is a Hayden 4797 "Heavy Duty" that has a 3/4 shaft pilot and includes a stepdown sleeve for the smaller shaft.

The part number 2797 clutch has to have 3.75 inches from the mounting flange face on the pump shaft (remember to include the pulley clamped in there) - to the radiator. It also has to fit over the shaft nub while you are putting it on. The clutch housing sticks out the front and doesn't really need a much room as the fan - but I wouldn't fit it too close.

I don't have the time to invent one - but it would be neat to have a clutch that simply fits over the nose of the pulley. There are some new (diesel) truck clutches that are pretty flat - and have an electric actuator with a single wire that goes in the front. Those look like they have some possibilites - but seem to be way more expensive than we would wish.........

A donut shaped electric clutch part - that fits on a smaller pulley - ought to do the trick. Then you could use an electric thermostatic fan controller to turn it on and off.