It's easy to determine just by observation that more blades move more air, everything else being equal. More surface area, more leading edges, more "solidity" factor (less non-productive area). Why aren't there 2 or 3 or 4 blade fans listed for heavy duty cooling instead of 7 blade?
Welp, since Denny Manner was a Buick Engineer that designed these engines, I kinda value his opinion. Besides it worked.
Not debating What the manual you guys And Dennis. Just saying there was discussion of the fan blades that looked like blades were broken off . Gobble lots of air. That being the purpose of the big gaps in the pattern. Did not mean to drift of topic.
You guys are way overthinking this. Just use what was designed by guys that knew far more than we do. Every part was designed to work as a whole. Mix and match at your peril.
