The 1970 model year marked a significant transformation for Plymouth’s Valiant lineup, with designers aiming to inject a dose of “muscle” into the previously understated model. The result was the Duster, a car that, while sharing its chassis, floorpan, front-end styling, drivetrain, and suspension with the Valiant, presented a distinctly different persona. Its more steeply raked windshield and fastback roofline created a sportier silhouette, setting the stage for a new era of performance-oriented compacts.
Under the hood, the Duster offered a diverse palette of four powerplants. Buyers could opt for two slant-six engines, displacing 198 or 225 cubic inches, or choose from two V8 options: a 318 or a potent 340 cubic inch mill. Horsepower figures ranged impressively from 125 hp in the smaller slant-six to a formidable 275 hp in the high-performance Duster 340. This performance variant was remarkably accessible, priced at just $400 more than the base model, yet it came equipped with a four-barrel carburetor, a three-speed manual transmission, a heavy-duty suspension, and front disc brakes, among other enhancements.
Initially, the car was badged as the Valiant Duster. However, by 1971, the “Valiant” moniker was dropped, solidifying the Duster’s independent identity. The Duster 340 received a distinctive “sharktooth” grille, and a new Duster Twister appearance package was introduced. This package allowed lower trim models to emulate the Duster 340’s aggressive styling, featuring Rallye wheels, side stripes, the “sharktooth” grille, a flat black hood with scoops, and bucket seats, offering a taste of performance at a more attainable price point.
The subsequent year, 1972, saw a recalibration of power figures across the Duster range. Plymouth adopted the SAE Net standard for horsepower ratings and reduced compression ratios, leading to a revised output for the Duster 340, now rated at 240 hp. Concurrently, Dodge discontinued the 198-cid slant-six. The Twister models also saw aesthetic adjustments, losing their special hoods and grilles, while the Duster 340’s single hood scoop was replaced with a dual scoop design.
A significant redesign arrived in 1973, bringing a refreshed front end characterized by the introduction of larger, federally mandated 5 mph bumpers, alongside new taillights. The lineup expanded with the addition of the Space Duster trim, joining the Twister and the popular Gold Duster model, which had first appeared as a decal special in 1970. The Space Duster was designed for practicality, featuring a folding rear seat and a carpeted trunk, significantly enhancing its cargo-carrying capacity.
The most notable change for 1974 was the replacement of the highly regarded 340 V-8 with a larger 360 V-8 engine. The following year, 1975, brought another restyled grille and introduced the Feather Duster trim. This model featured the 225-cid slant six and incorporated lightweight aluminum components to reduce overall weight, contributing to an impressive fuel economy rating of 24 mpg in city driving and 36 mpg on the highway.
In its final iteration, power outputs saw another decline across the board. The Duster 360, in its last year, produced 220 hp. After achieving remarkable sales figures exceeding 1.3 million units, the Plymouth Duster was discontinued. However, the Duster name would continue to resonate within Chrysler’s portfolio, appearing on subsequent models such as the Volare and Sundance, a testament to its enduring legacy in the automotive landscape.