Gang,
Back in '66 (and I'm guessing other years) Olds varied the water pump pulley outer diameter. Seems like the non-a/c cars had a larger one, and a/c cars had a smaller one.

Do you have opinions about which size is prefereable? I'm guessing the a/c or heavy duty (smaller) would spin the compressor, alternator, power steering pump and water pump a bit faster, so it might be preferable.

What do you all think if I'm looking for a cool running, good charging, good steering car? Just stay stock?

 

I think the pulley diameter was matched to the water pump impeller diameter. Chris Witt had posted some good info about this a long time back but I don't have a link handy. Seems I remember a discussion about spinning the impeller too fast could cause cavitation and reduce cooling.