The Plymouth Roadrunner was a car built by Plymouth (a division of the Chrysler corporation) in the United States between 1968 and 1980. In 1968, the original batch of muscle cars were in the opinion of many moving away from their roots as relatively cheap fast cars as they gained more and more options. Plymouth intended to go back to the drawing board and reincarnate the original concept.
Paying $50,000 to Warner Brothers to use the name and cartoon likeness of their Roadrunner character (as well as a "beep-beep" horn!) , and using the Plymouth Belvedere as a base, Plymouth set out to build a back-to-basics muscle car. Everything essential to performance and handling was beefed-up and improved; everything inessential was left out, to save weight (and thus improve performance). The interior was spartan, lacking even carpets, and few options were available. The standard engine was Mopar's old favorite 383 ci V8 rated at 335 bhp and 425 lb-ft of torque; for an extra $714 Plymouth would fit a 426 Hemi rated at 425 bhp and 490 lb-ft.
Plymouth expected to sell a couple of thousand of these in 1968. Actual sales numbered around 45,000. The 1968 Roadrunner is one of the true muscle car classics.
1969's model was little changed; the introduction of a 440 ci V8 (the intermediate powerplant despite having cubic inches on the more powerful 426 Hemi), optional bucket seats and a convertible model were the only additions. Sales almost doubled, to 82,109. 1970 only differed in the option of a retractable 'Air Grabber' hood scoop, but sales were down to less than 1968's total. That year also saw the production of a streamlined NASCAR racing version, the Plymouth Superbird
In 1971, the bodywork was completely changed, to a more rounded, somewhat shark-like shape with deeply inset grille and headlights, similar to the Dodge Charger of that year. That year saw the writing on the wall for the muscle car, and performance was already down thanks to new emissions and fuel economy legislation. Little changed through 1974, except for steadily decreasing power output. 1974's model was really the last true muscle car Roadrunner.
1975's model was (for one year only) based on the Plymouth Fury, and after 1976's switch to a Plymouth Volare platform, the Roadrunner was barely more than a trim and graphics package on what was fundamentally an economy car. These, Roadrunners in name only, were built through 1980 before Plymouth dropped the model altogether.