Plymouth developed the Road Runner to market a lower-priced, basic trim model to its upscale GTX.
[1] The Road Runner was based on the Chrysler B platform (the same as the Belvedere and Satellite), as a back-to-basics mid-size performance car.
The interior was spartan with a basic vinyl bench seat, lacking even carpets in early models, and few options were available — such as power steering and front disc brakes,[1] AM radio, air conditioning (except with the 426 Hemi) and automatic transmission.
This placed the Road Runner third in sales among muscle cars, with only the Pontiac GTO and Chevy's SS-396 Chevelle outselling it.
The 1969 model kept the same basic look, but with slight changes to the taillights and grille, side marker lights, optional bucket seats, and new Road Runner decals.
An Air Grabber option (N96 code) was introduced this year; it consisted of a fiberglass air duct assembly bolted to the underside of the hood that connected to twin rectangular upward-facing vents in the hood with Rallye red vent screens.
[9] The 1970 model year brought new front, and rear end looks to the basic 1968 body, and it would prove to be another success.
Updates included a new grille, cloth & vinyl bench seat, hood, front fenders, quarter panels, single-piston Kelsey-Hayes disc brakes (improved from the rather small-rotor Bendix 4 piston calipers of '68 - '69 ), and even non-functional scoops in the rear quarters.
A switch below the dash actuated a vacuum servo to slowly raise the forward-facing scoop, exposing shark teeth decals on either side.
Although a heavy-duty three-speed manual became the standard transmission, the engine lineup was left unchanged, relegating the four-speed to the options list along with the TorqueFlite automatic.
The Plymouth Duster I was a high-performance concept car version of the Road Runner produced in the late 1960s.
A set of adjustable spoilers on the rear fender's side (near the gas tank filler cap) helped prevent side-to-side yaw when slipstreaming in a race, with two more of them on top behind the driver, plus spoilers in the front as rock shields to reduce frontal lift.
The Daytona featured an elevated spoiler raised 23 inches off the trunk deck by upright pylons and an aerodynamic nose cone.
The Charger 500, especially, and the Daytona to a lesser degree struggled to equal the fastback Ford Torino Talladega and Mercury Cyclone Spoiler II in 1969.
While spectacular[peacock prose] on the track, consumer response was lukewarm, leading a few dealers to remove the wing and nose, making them appear more like normal Road Runners.
The Superbird actually used the front fenders and a modified hood from the '70 Dodge Coronet that lent themselves better to the nose design.
In 1971, the coupe bodywork was completely changed to a more rounded "fuselage" design in keeping with then-current Chrysler styling trends, including a steeply raked windshield, hidden cowl, and deeply inset grille and headlights.
The interiors could be ordered with 6-way power leather seats, thick deep-pile carpeting, and additional sound-proofing was installed.
It also saw the introduction of the 340 4-BBL option and a detuned 383 "Road Runner" engine with 8.7:1 compression and power dropping to 300 hp (224 kW).
In return, Road Runners with the 340 and 383 engines received a standard insurance rating without the costly premiums normally tacked onto muscle cars.
For 1972 power ratings on all engines looked much lower on paper due to the new SAE net measurement system.
The famed 426 Hemi was discontinued for 1972, and only five 440 Six Barrel equipped cars were produced before this engine option was dropped (it was determined the 440 six-packs could not meet the stricter 1972 emissions regulations) in the fall of 1971.
The 1971-72 Road Runner sheet metal was used by several NASCAR racing teams for their racecars and ran well on the circuit during the 1971-74 seasons.
The base engine for the 1973-74 models had dropped down to Chrysler's workaday 318 CID V8 but equipped with dual exhausts which bumped the power up to 170 hp (127 kW).
The 440 cu in engine, boasting 280 hp was still available for 1973 and 1974, but only mated to the 727 TorqueFlite automatic, with 3.55 sure-grip 8 3/4 rear axle gearing available.
Like Fury, the Road Runner could be ordered with plush interiors, a rally instrument cluster in the dashboard, power seats as well as windows.
The Road Runner came with a blacked-out grille and a special stripe treatment to distinguish it from the Fury, as well as a heavy-duty suspension with front and rear sway bars and Rallye 14-inch or 15-inch wheels.
The new F platform was marketed as the Plymouth Volaré, and the new Road Runner became a trim and graphics package primarily.
The standard engine was the 318 V8 with the 360 CID V8 offered as an option (with a two-barrel carb for 1976-'77 and single exhaust) producing 160 hp (119 kW) and only paired with the three-speed automatic transmission.