The Superbird was developed as a direct follow-up to the 1969 Dodge Charger Daytona, the two cars forming the famous pair of "aero-cars" or "winged warriors" produced by Chrysler's divisions for high-speed superspeedway racing. The Dodge Charger Daytona had dominated 1969 but Plymouth needed its own weapon for 1970, and the engineering team incorporated lessons learned from the Daytona's season of competition.
The body modifications were extensive. A protruding aerodynamic nosecone added nineteen inches to the Road Runner's original length, smoothing airflow at the front of the car. The rear window of the standard Road Runner was recessed, so the Superbird received a flush rear backlight treatment to eliminate turbulent airflow at that point. The car's most iconic feature was the tall rear stabilizer wing, mounted on vertical struts high enough to place it in clean, undisturbed air above the roof. The wing generated meaningful downforce on the car's rear axle at racing speeds; at speeds below 60 mph, however, the aerodynamic modifications provided little benefit compared to a standard car.
NASCAR required that any car raced in its Grand National series must be available to the general public and sold through dealer networks in sufficient numbers. For 1970, NASCAR had raised the minimum production requirement from 500 cars to one car per every two of the manufacturer's United States dealerships. For Plymouth, that translated to a minimum of 1,920 Superbirds. The company built approximately 1,935 cars for the United States market, with an additional 34 to 47 believed shipped to Canada.
Three engine options were available: the 426 cubic-inch Hemi V8 producing 425 horsepower, the 440 Super Commando Six Barrel with three two-barrel carburetors producing 390 horsepower, and the 440 Super Commando with a single four-barrel carburetor producing 375 horsepower. Only 135 of the production Superbirds carried the 426 Hemi engine.
A central motivation for the Superbird's creation was to bring Richard Petty back to Plymouth. In autumn 1968, Petty had left the Plymouth NASCAR team for Ford, a significant blow for Chrysler. The Superbird was designed with Petty specifically in mind as an inducement to return.
The strategy worked. Petty drove the Superbird in 1970 and performed exceptionally well against strong Ford competition. He won 18 of the 40 races he entered from a 47-race season, added 9 other top-five finishes, and placed fourth in the overall championship despite missing seven races due to an injury suffered at the 1970 Rebel 400.
NASCAR's rules implemented for the 1971 season limited the aero-cars to an engine displacement of no greater than 305 cubic inches, or they had to carry substantially more weight compared to competitors. The power-to-weight consequences of either option rendered the Superbird and its Daytona sibling uncompetitive, effectively banning both from meaningful NASCAR participation after their single-season spotlight.
The Plymouth Superbird raced for just one NASCAR season and was produced for only one model year, yet it left an outsized legacy. Its extreme styling proved too unconventional for the buying public and many examples sat unsold on dealer lots as late as 1972, with some converted into standard Road Runners. In subsequent decades the Superbird became a highly sought collector car, regularly commanding prices of $200,000 to $450,000 at auction depending on engine specification and options. The car's brief but spectacular NASCAR career and its unmistakable silhouette made it one of the most recognized machines in the sport's history.