Water pump pulley size

[dalekerr]

I have a 67 with sbc motor and  I added vintage air. Since adding the air the car runs hot up to 230 degrees while sitting idling  after 10 minutes or so. It never gets above 190 while driving at highway speeds. The car has a new 3 core aluminum radiator with shroud, new 7 blade fan and clutch. I noticed that the crankshaft and water pump pulleys are the same size.

I can rev the motor rpm up and bring the temperature down.

My question is would possibly  changing the crankshaft pulley to a larger size or putting a smaller water pump pulley solve my running hot while idling issue?

Yes the timing is set correctly.

Opinions please

Thanks in advance

Dale Kerr

[KurtS]

I'd start with the pulley sizes used with AC vs non-AC cars.
http://www.camaros.org/engine.shtml#PulleySpreadsheet

[z28z11]

I notice you didn't spec what thermostat you are using, 180 or 165 degrees ? Stock water pump, OE rebuilt or aftermarket ?

Regards,
Steve

[dalekerr]

180 stock water pump.

[dalekerr]

Ok I ordered and installed a new crankshaft pulley 7.25 and a new water 6.3 pump pulley today. This seems to have solved my running hot while idling. The car is now running about 10 degrees cooler while driving and idling. 

I read on another site about pulley sizes and  cooling.