425 V-8 `78 Deville-- Cooling system self bleeding or not?

On any cooling system, I keep the idle up after adding maybe a gallon to an empty system. A friend holds the idle at about 1500 RPM, heater on max heat, fan on low. As I add the remainder, the level will drop quickly. I continue to add and keep the idle up. Once it tops off I quickly install the cap and tell my buddy to release the throttle. Because the engine and radiator are about the same height underhood on your car, you have less chance of trapping air. Burping the system started when hoods were sloped down and the radiator was mounted lower than the engine or the engine faced to the right.