By the way if you remove the thermostat restriction and the car runs hotter it's not because the water is going "too fast". It's because it's barely moving at all. Removing back pressure on the water pump can cause cavitation very easily and in hot water easier than cold. So you need the restriction and the pressure cap. You also need antifreeze to raise the boiling temp of the coolant and to prevent corrosion.

Car designers figured all this out years ago.