Plymouths were usually slightly smaller (shorter wheelbase) and had less standard trim options. Aside from cars like the GTX or Sport Fury GT Plymouth was intended to be the 'entry-level' marque for Chrysler to competed with Chevrolet and Ford. Dodge was a step above Plymouth and was meant to compete with Mercury and Pontiac. Then you obviously had Chrysler brand, and Imperial at the top (GOD I would love to have one of those...).quote]
That is the way I allways thought it was.
