Plugging the by-pass hose pros and cons

The bypass hose relieves back prseeure on the water pump when the thermostat is closed. If nothing else the block will cost mpg and horsepower .
May shorten the life of the pump.

I agree on that, I would still run it. At the very least have some holes in the t-stat, or maybe run the line that goes to the heater core into the intake manifold?