The hot coolant from the engine exits the intake manifold, goes thru the heater valve to the heater core and returns to the water pump. Since there's no flow thru the circuit when the heater is off, both the manifold and waterpump ports can get plugged. OTOH, connecting the two ports together, in theory, will allow more coolant flow and in effect bypass the bypass.
I'm with Sniady on trashing the heater; the weight savings is probably worth a half second a lap!
