How many fan blades in thermal fan clutch 79 350

[truckin 79]

I finally got around to changing thermostat out in the 79 truck with a 350 and it seemed to help with low temp in truck. The previous thermostat was a 180 and so the 195 seemed to help. The temp gauge in truck does not seem to move much after swap though, it could be sender. I grounded out wire and gauge needle moved all the way to the right. I have a fixed fan blade on truck now but I am thinking of switching to a thermal fan clutch. I figured with thermal fan clutch it will just freewheel most of the time which could save gas a little and keep truck running in the sweet spot of operating temperature. So can someone tell me how many blades there are on a 79 1/2 ton with a 350. I am just going to pick up fan and clutch at junkyard, it will cost about 20.00