Those are nice cars. I had a '72 300 SEL 4.5 many years ago. Beauty, dripping with luxury inside. 280 is not quite as trimmed. Tip, has a transistorized ignition to reduce the current going through the points. Slightest bit of dirt would cause the engine to get ornery. Kept a matchbook in the car. When it acted up, pop the distributor cap, run the matchbook cover between the points and you're good to go!