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Forgotten American Muscle: Plymouth Duster 340

It had a wonderful start but then, well...

Some muscle cars have received all of the fame, status, and ever increasing auction prices. And then there were a few that, despite having a loyal following that’s still active today, nearly slipped through the cracks of American automotive history. The Plymouth Duster was one of them. We all know the Plymouth Barracuda and how it now sits at the thrown of classic muscle car royalty. It rightly deserves to be there, but we also shouldn’t forget another Plymouth from the same era that deserves to be recognized for its own reasons.

The Duster hit the market in late 1969 as a 1970 model, which was kind of late when compared to other muscle cars of the time. Basically, the Duster was nothing more than an altered Plymouth Valiant, a simple compact sedan and coupe.

But Plymouth smartly wanted to further capitalize on the success of not only the Valiant, but also the 340 V8. The goal was to build a sporty, semi-fastback coupe version of the Valiant for a bargain price tag. The Duster shared the same front end and interior with the Valiant, but all of the sheet metal, along with the aforementioned fastback look, and also the taillights, were new. For 1970 only, Plymouth placed the Valiant badge above the Duster badge on the front fenders; proof that management wasn’t sure a sporty Valiant with its own name would take off. Well, they were proven wrong. The Duster formula was a huge success.

Not only did the top-end Duster offer that 340 V8 with 275 hp and 340 lb-ft of torque, buyers could also opt for three smaller and less powerful engines: two inline-sixes rated at 125 and 145 hp, and a 318 V8 with 230 hp. All were affordable and, when combined with the Duster’s styling, an overall winning formula. The 340 V8 also had respectable performance numbers: 0-60 mph in 6.2 seconds and the quarter-mile in 14.7 seconds at 94 mph. That was an incredible bargain for a list price of $2,547; the 340 V8 was only a $400 option. Just to compare, the Plymouth Road Runner based at $2,900 and the Ford Mustang Mach I cost at least $3,300.

Other notable bits Plymouth gave the Duster top-end 340 included a four-barrel carburetor, dual exhausts, floor-mounted three-speed manual transmission, a heavy duty suspension with larger diameter torsion bars, a front stabilizer bar, front disc brakes, extra leaf springs, and a special instrument panel with a tachometer and 150 mph speedometer. The Duster was such a huge success in its first year that Dodge quickly called their Plymouth counterparts and requested a version of its own, which became 1971’s Demon. Plymouth made only slight changes to the Duster for ’71, mainly the Valiant badges were permanently removed and even the Plymouth logo was taken out of the front grille.

A new package, the Duster Twister, was released, but it was nothing more than the 340’s appearance for the less powerful inline-six and 318 V8 models. That included side stripes, a matte-black hood and a shark-tooth grille. An electronic ignition became standard for all 340-equipped Dusters in ’72. More significant changes didn’t happen until ’73 and that was only because the Valiant received design updates. The Duster was given a refreshed hood, front fenders, grille, bumpers and taillights. Also worth mentioning – and this was good for the younger buyers who could afford the Duster – was a rear bench seat that could be folded down. Plymouth claimed this was to allow more cargo, but we’re sure people found other uses for it.

Anyway, in 1974 Plymouth dropped the 340 V8 entirely, replacing it with a 360 V8. That wasn’t a good thing. Remember, the aftermath of the oil crisis was still being felt and automakers were forced to deal with it in ways unappealing to muscle car fans. That 360 V8 had less horsepower (245 hp) despite the greater displacement. Even though torque was increased, the 360 couldn’t outrun its 340 predecessor. Things got worse for ’75. The top-end V8 was detuned to 230 hp because an air injection system was added and it didn’t have a catalytic converter. That became known as the "smog pump." 1976 was the Duster’s final year, and it was kind of a sad way to go out.

For example, the 360 V8 dropped another 10 hp and the remaining engines, the inline-six and 318 V8, were detuned as well. Plymouth tried to hide what was happening (the death of the muscle car) by offering new trim packages. The most well-known was the inline-six-powered Feather Duster. All it really offered were lightweight parts made from aluminum, such as the bumper brackets and intake manifold, which cut about 190 lbs. As for the 360 V8 option? It was no longer anything all that special. Plymouth simply called it the Dart Sport 360. Output remained at 220 hp. And that’s where the Duster story comes to an end. It greatest years were the first ones, right up until the 340 was dropped.

The Duster was the right type of muscle car at the right time; affordable, slick styling, and more than respectable performance. Call it the bargain muscle car if you’d prefer, but the Duster 340 V8’s life was sadly cut short because of factors beyond Chrysler’s control.

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