The RoadRunner is one of the most recognized muscle cars from the 60's. It was originally conceived as a stripped down performance car at a reasonable price. The intial goal was to build a car that would do 100mph in the 1/4 mile and cost less then $3000. The car came standard with a modified 383 4-Barrel that used the cylinder heads, intake manifold, exhaust manifolds, crankcase windage tray, camshaft and valve springs from the 375 hp high performacne 440 V-8. This special 383, rated at 335 hp, was only available on the roadrunner, and no other Plymouth car. (However, it was available in the Dodge equivalent, the Super Bee). The RoadRunner has become an icon for 60's musclecars.

In 1969, things got even hotter with the introduction of the 440 Six Pac. (Officially it was the 440-6bbl). Also in '69 were some more performance oriented rearend ratios, etc.