Q: White smoke coming from the water pump out of radiator hose outlet

Hi there. Assuming, proper procedure was followed replacing the head gaskets. The original cause for overheating must of been overlooked. The thermostat stuck closed, the radiator restricted, the radiator cooling fan(s) inoperative. The cylinder head and/or cylinder head gasket issue should be confirmed before disassembly. Removing the spark plugs and pressure testing the cooling system, should help identify which cylinder has coolant contamination. The machine shop you are using should be able to check for cylinder head cracks. I recommend having your vehicle’s engine overheating issue diagnosed and repaired by a certified technician, such as one from YourMechanic, if you’d like further help.