[TR] Drive pulley size reduction, thin belt H2O/Amp speeds

[Dan Cronin]

1/26
I recently purchased a ATI Damper only to discover that the drive pulley hub that comes with it is appro. 3-5/8" diameter at outer lip vs. the Alloy thin belt damper/pulley's appro. 5-1/8" diameter (stock pulley was appro. 5-1/2").
The thin belt water pump pulley is appro. 4" at outer vs stock's appro. 4-1/8, so no diff. there.  The thin belt alternator pulley is appro. 2-3/4" outer, vs stock generator's 3-1/4".  Since output is apples to oranges between alternator and generator am wondering  if there is a consensus on what speeds the alternators should run at---am using a Delco 63 amp unit.  Am also wondering if the slower speed that the water pump will run at will be a problem as I am going to be using the six vein aftermarket pump in alloy housing and running an 12" electric fan.  Thoughts?  Suggestions?  Other's experiences?
Thanks, Dan