All the years that I had my car I used an aluminum Floe Kooler water pump that was belt driven and high volume. No under drive pulleys or anything else and it never did cause me any problems, even when in town on our 118 degree days. And I could just rev the engine up a little and see the temperature gage start back down from the city traffic. But I also had aluminum heads, intake, and everything was ported and all the water flow areas had been cleaned and polished when the engine was built. So that probably helped some.
Ron
