that's how i have mine setup.The return line always needs to go to the suction side of the water pump for proper circulation (bottom rad hose connection or passenger side of the block between radiator connections). The connection going to the heater goes just before the thermostat on the head. So the flow circuit bypasses the thermostat and starts giving heat before the thermostat opens. Same proven set up as an early 89 - 93 Dodge Cummins. Use a shut off valve going to the inlet for Summertime, either a vacuum valve or a ball valve.