67 Dart 270...Project Old School

nice project! :-)
about the heat issue... did mopar deliver different sizes on the water pump pulley? if the water pumpe spins too slow, it will also cause overheat problems? but then the problem will be only idle and cruise,and not on the highway I think...

I dont remember vlearly, but think I read somewhere the stock 5blade viscous fan pulls about 3000cfm at idle fully engaged? anyone?