Which one flows better, factory 6 blade water pump or 8 blade

Nothing to get upset about.

I was assuming when you said "zillion groove AC pulley" you were talking about the crank pulley ?
Not at all.
Water pump pulleys came/come with more than one groove as well, depending on motor and car...but I get why 'zillion groove' =crank pulley. Neat when they have been bent slightly...and they just lightly wobble on the nose of the crank at idle. Looks so shitty.
I'm out, I offered my 2cents on water pumps.