how about the slower moving coolant our car tend to have an issue with heat, and slowing down the water pump cant be good for that and slowing down the alternator will lessen the power output (especially at idle)
Hmm, putting a smaller diameter pulley on the w/p should increase the rpm, shouldn't it? I researched that solution to overheating last summer, and came up with a smaller diameter pulley from a 1971 400 that was more or less a perfect fit. The biggest problem would otherwise to find a pulley with exactly the right offset.
Actually I'm still waiting too see the results of the operation. I did it late last summer, and after that there wasn't any really hot days. So I guess the real test will be this summer instead.
However, what I can see is that the temp needle stays one notch below the mid position (have gauges), before the pulley job it was somewhat higher on the scale. Again though, it might be related to the outside temp.
A smaller drive pulley will slow down the rpms on the pump. But a smaller pulley on the driven end, like the water pump, will actually increase the RPM of the pump increasing the flow. That is why the engine was running cooler.
