Classic/Antique Car Repair: 1937 chevrolet overheating

Question
I have a 1937 chevrolet completely original having trouble overheating very quickly when in traffic or at a stop light.Did all the normal ngs radiator sent to radiator shop, new rebult water pump, tried to flush the block, new thermostate,installes a electric fan in front of radiator ect.

Answer
What does the temperature run at when driving down the road? Does the radiator boil when it over heats? What is the ignition timing set at? Retarded timing could cause it to run hot. Have you checked the coolant temperature with an eternal thermometer ? I use a kitchen thermometer in the radiator neck. Get back to me. Brad