[eagle]

This subject has been discussed many times. The takeaway is, a marginal cooling system can benefit from the restriction of the thermostat or cutting down impeller blades. However, the benefit is seen in reduced negative pressure in the engine block, making steam flashover less likely. The reduced flow though does create less turbulance, and turbulance is good for heat transfer. Much better solution is to get the cooling system up to snuff. Clean block and clean or replace radiator.