[h=2]Plymouth Roadrunner Superbirds were used by cops at a famous Georgia speed trap. [/h] Source: Michael Furman/RM Sotheby’s

Along with the nearly identical Dodge Daytona, the Roadrunner Superbird was Plymouth’s aerodynamically-enhanced homologation special for the 1970 NASCAR season.

While its pointed beak and comically large rear wing made a difference on the track (top speed was upwards of 180 miles per hour), it’s polarizing looks, Loony Toons decals (Plymouth licensed the Road Runner character from Warner Bros.), and 18.4-foot length made it a sales dud, and unsold Superbirds sat on dealer lots until the mid-’70s. With fewer than 3,000 built, the rare and iconic ‘Bird represents the peak of muscle car madness. This car sold for $363,000 by RM Sotheby’s in 2013.