Whats the difference in these two fans?

[DR]

Just curiousity... They are both from 350 chevys. One I took out of a 2x 86 c10 with an obviously transplanted engine, and one from a 4x4 85ish Suburban. I honestly cant remember which fan came from which. They are simular in size, but the blades are very different. One has long narrow blades, the other short wide blades. Does one move more air than the other?

 

[K85 Octane]

complete guess but I think looking at them, the top one moves more air

my 85 (and at this point who really knows what is original anymore) has a fan that looks just like the top one but with only 5 blades IIRC

 

[ryoken]

the top one has the heavy duty clutch..