The smaller fan properly installed in the shroud should move more air than the larger with no shroud. I dont know about number of blades, but the "pitch" of the blades will make a difference on air movement. More pitch, more flow.
"Do not walk behind me, for I may not lead. Do not walk ahead of me, for I may not follow. Do not walk beside me either. Just leave me alone, you're starting to freak me out."
1957 GMC 150
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