On the heater side, I built a 'manifold' out of 3/4" copper fittings to interface the two hoses to the heater core on one side, and the engine on the other side. On the engine side, one hose goes up to port on the intake manifold next to the thermostat. The other hose goes into the suction side of the electric water pump. The crossover pipe has a 1/4" diameter restriction inside. This provides a bypass for the water pump when the engine thermostat is closed. The bypass prevents water pump cavitation and improves cooling by allowing coolant to circulate the engine block during warm-up. For the hell of it I powdercoated the piece cause I haven't powdercoated anything for a long time.
