Educate me on why 340 fan is not symmetrical

[Dale Davies]

Why is it on some radiator fans the blades are symmetrically spaced and some are not. In the process of purchasing fan for my 340 but am reluctant due to the blade orientation. It's a 340 fan with 2 1/4 pitch part number 2863 215. My research indicates this is for a 340, Mine is a 70 model engine going into a 68 Barracuda. Any help would be appreciated.

Evenly spaced blades, symetrical, tend to noise from the even "pulses" as the fan blades hit the airstream through the radiator. The 5 blade fans could be manufactured with the blades equal spaced, but that would not accomplish a desired result. Three are moved slightly closer together and the two remaining are noticably closer on the opposite side. This maintains static and dynamic balance and breaks up the frequency of the air pulses, reducing fan induced noise.

 

[Jim Kueneman]

Also, so you can get your hand and a wrench in to undo the bolts.

And you can get the AC clutch off without removing the fan.