Overdriven pulley how much is too much?

Gotta ask a question, if you install the pulleys and pumps, and everything is cooling really good, so good engine runs at 130 - 140 degrees, less in winter, - no heat from the heater, are you going to put a thermostat in to do it's job, and restrict all that flow, - so the engine can come up to operating temp, or run it cold ?