Need correct water pump pulley diameter for small block V8

[femtnmax]

The water pump pulley I have is off the 318 that came in the car, IE 74 chally with 318 and A/C.  The pulley is close to 6 1/4 inch diameter, which is large enough that the power steering belt cannot be removed without taking the pulley off the water pump....there is very little room between the water pump pulley and crankshaft pulley.  Cooling system details include :
Now have a higher flow water pump (replaced the 6 blade impeller with 7 blade).  Upped the compression to 10.5:1 and have aluminum heads.  Have a 22 inch wide radiator, and have 18 inch diameter fan with clutch, and will have a fan shroud.  Will be running a 180 degree thermostat.  Car will NOT have A/C.

My questions:
Is it common for the two pulleys to be so close, and have to take pulley off to change power steering belt?
Based on your experience, do I need to change to a smaller diameter water pump pulley to drive the cooling system flow at a faster rate?  I would like to use a factory pulley. 

[Strawdawg]

http://bouchillonperformance.com/BPEpulleys.asp

6 7/8"?

[femtnmax]

Thanks for the reply.  I have a 3 groove crank pulley that BPE doesn't show, so looks like I have a mishmash of pulleys.  I'll get a correct set from the parts yard.

[Aussie Challenger]

You don't want to run the water pump too fast or it will just cavitate.

[Strawdawg]

Thanks for the reply.  I have a 3 groove crank pulley that BPE doesn't show, so looks like I have a mishmash of pulleys.  I'll get a correct set from the parts yard.

I think this suggests that the three groove is pre '70

http://www.forabodiesonly.com/mopar/archive/index.php/t-26067.html

[femtnmax]

thanks strawdawg.  the a-bodies write up and pics showed what I need.  I picked up the correct pulleys at the parts yard off a 68 coronet, non a/c and power steering, and spent only $20.

[Strawdawg]

Good deal....I should have let you look for the PS pulley for me!

[femtnmax]

The 1968 pulleys were for cast iron water pump and did not work out.  The same parts yard had a mid 70-80's dodge pickup that had the correct pulleys for small block with aluminum water pump.  We traded pulleys and the truck pulleys fit great.
Thanks again strawdawg for "pulleying" me in the right direction!