High volume water pump?Yes/No

It's all about surface area. The area inside the cooling jackets and the area of the radiator core. The speed of the cooling media makes no difference (air never goes through the radiator too fast to take the heat away). The potential problem with too rapid flow through the heads comes from turbulence induced cavitation. That is, the water actually begins to slosh and churn causing localized lower pressure areas that can become steam pockets. Here typically a restrictor is added to regulate and balance the flow. This is more a function of how the water moves through the heads rather than the pump

The output of an impeller type pump will raise more or less with RPM until the impeller cavitates or there is a restriction on the intake or output. From that point on, the output remains basically constant. The pump will only deliver what the cooling system can flow, and requires no further regulation. The output of a positive displacement pump, like an oil pump, increases in direct proportion to RPM until restricted on the intake. This is why oil pumps are regulated with a bypass mechanism, otherwise destructive pressures would quickly develop. In either case there is a basic rule for pumps. Once you have enough it is enough, anything more than that is still only enough.

Milodon 16251 and Flowkooler 1701 are supposedly high flow early style pumps. They may help a little at lower street RPM, and probably are worthwhile if only because they'll have a nicer bearing and seal than a typical parts house cheapie. I plan to use the Milodon on my 65.