From Wikipedia:
The Plymouth Superbird was a highly
modified, short-lived version of the Plymouth Road Runner with
well-known graphics and horn sound. It was the factory's follow up stock
car racing design, for the 1970 season, to the Dodge Charger Daytona of
1969, and incorporated many engineering changes and modifications (both
minor and major) garnered from the Daytona's season in competition.
The
car's primary rival was the Ford Torino Talladega, a direct response to
the Mopar aero car. It has also been speculated that a motivating
factor in the production of the car was to lure Richard Petty back to
Plymouth. Both of the Mopar aero cars famously featured a protruding,
aerodynamic nosecone, a high-mounted rear wing and, unique to the
Superbird, a horn which mimicked the Road Runner cartoon character.
Superbirds
equipped with the top-of-the-line 426 cu in (7.0 L) Hemi engine with a
pair of four barrel Carter AFB carburettors (2x4bbl) producing 425 hp
(317 kW) could accelerate from 0 to 60 mph (97 km/h) in 5.5 seconds.
