Dodge Demon 340: Looking Closer at a Legend

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With new emissions controls looming, Dodge needed a nice compromise to keep high-performance owners happy. The solution was the Demon 340.

The Dodge Dart Demon 340 was a top-performance upgrade in 1971 with a 340 ci (5.6L) V8. The engine produced 275 hp with an 8.5:1 compression ratio and a 4-bbl carburetor. The Demon 340 helped Dodge owners transition from high-powered muscle cars toward more fuel-efficient vehicles.

With muscle car sales waning, Dodge needed to reinvent itself in 1971. Increasing gasoline prices, insurance costs, and tightening emission controls were becoming everyday realities, forcing the company to adapt to survive. The large displacement engines that had built Dodge’s muscle car dominance over the previous decade weren’t viable options as Americans began to embrace a rising flood of gas-sipping imports. Dodge needed a car that could appeal to its high-performance base and still cater to an ever-changing automotive landscape. The result was the Dodge Demon, a more compact 2-door coupe with an engine that could make almost everybody happy (except for religious groups). The Dodge Demon would become a favorite classic muscle car, built to compete in a new world. Let’s take a closer look at the Dodge Demon 340.

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The Background To The Dodge Demon 340

As the sixties drew to a close, Dodge had established itself as a muscle-car performer. The Charger and Challenger were scooping up sales with their new designs, and Dodge wanted more. Younger buyers showed they did not care about a lack of amenities as long as the car was cheap and fast. In this vein, Dodge found another home for its 340 high-performance engine, a new model called the Dart “Swinger.”

The Swinger would sell reasonably well (16,637 units) in its first year, but sales dipped the following year, even though Dodge promoted it as the high-performance variant of the Dart. When Plymouth redesigned its Valiant for 1970, offering a fastback version called the “Duster,” customers snapped it up almost twice as much as the Swinger 340. The initial sales for Plymouth were so good that Dodge demanded and received its version of the fastback Duster, which they promptly named the “Dodge Dart Demon,” for the ‘71 model year.

Dodge trumpeted the new car in advertising with a “Scat-Pack” designation (an ad campaign that the company had begun in 1968 to promote its high-performance vehicles). The

sales brochure for the Demon proclaimed that “while the Demon might not be their “lowest priced performance car, but you’d never know it by the way it keeps up with the big boys.”

Dodge received almost immediate backlash from conservative religious groups, who objected to glorifying the devil by naming a car after him. When Dodge incorporated a cartoon devil in its advertising (complete with a pitchfork) and a sticker on the car, the noise from the religious right only seemed to grow stronger. Eventually, Dodge bowed to the consumer pressure and changed the name to “Sport” after 1974.  

The Engine Of The Demon 340

In the mid-sixties, Chrysler developed the 340 engine as a high-performance version of the 5.2L (318 ci), with a larger bore and stroke (4.04 X 3.78). The engine was designed with high-flow heads, a two-stage intake manifold, stronger connecting rods, and other heavy-duty components. Dodge initially used the engine in the Dodge Dart GTS and Dart Swinger 340, while Plymouth stuck it into its ‘68 Barracuda. Over the next couple of years, the engine began to appear in other models like the Challenger, Charger Rallye, and Swinger over the next couple of years. In 1970, Dodge paired the engine with a Six-Pack carburetor set-up (three 2 bbl), which helped produce 275 hp.

Dodge paired the 340 V8 with a four-speed manual or three-speed automatic, which helped the Dodge Demon more than hold its own against its rivals. The higher output 340 could motor down the track, posting a 7.5 second 0 - 60 mph time. In comparison, the Dodge Charger with a 383 V8 posted a time only a few tenths of a second faster). While the engine wasn’t as powerful as the 426 Hemi, it was more than capable as a performer for the street, giving the Chevy SS a run for its money (7.1 seconds).

The Dodge Dart Demon started with the high-performance engine in 1971, but rising gasoline prices, increasing insurance premiums, and emission regulations forced Dodge to “detune” the V8 to an 8.5:1 compression ratio. Dodge tried to minimize the impact of the change by omitting horsepower ratings, but the power output fell to 240 hp. (Part of the decline can be attributed to the federal government's revamping of how horsepower could be advertised - net vs. gross).

Dodge experienced terrible sales for the 1972 model (8,700 Demon 340 units). Customers simply found the lower-powered Demon unworthy of their time or money. (In contrast, over 15k models of the Plymouth Duster 340 were sold). The decision to rename the Demon to the Sport (along with new styling cues) resulted in increased sales for 1973, almost doubling the previous year’s totals.

The Exterior Of The Demon 340

The Dodge 340 gave an aggressive athletic appearance with its long nose, dual scoops, hood pins, and rear spoiler. The front fascia consisted of two sectioned black grille sections with a wide chrome bumper undergirding the front end. Round headlights sit on the far sides of the front, with square high beams giving the car a distinct appearance. Many Demons sported dual thin stripes along the sides, matching the wider racing stripes covering both sides of the hood.

The rear taillights consisted of six vertical slats on either side (the outer four highlighted both tail and brake lights, while the middle two served as reverse lights on either side). The Demon had dual exhaust, E70 X 14-inch wheels, a Rallye suspension, and heavy-duty disc brakes.

Dodge claimed that the Demon was a compact car, and while the wheelbase was shorter (108 inches) than the Dart, Charger, or Challenger, the total length was similar to other Dodge models.

The Interior Of The Demon 340

The Dodge Demon was not a luxury car by any means. Dodge designed the car to appeal to your owners, who were more interested in performance than creature comforts. Even though it was a part of the Dart lineup, the interior copied the Plymouth Dusters almost completely. A standard split cloth and vinyl bench seat were included, with a simple padded dash and easy-to-read gauges with a 120 mph speedometer and a 6,000 rpm tachometer. Side seat levers could be manipulated to fold the front seatbacks forward, allowing access to the rear seat area. While the rear seat was not as cramped as Ford’s Mustang or the Chevy Camaro, it was small.

The Safety Of The Demon 340

While no car made in the seventies is as safe as current models, Dodge did commit itself to providing several safety features. In addition to seat belts (mandated since 1968), the company installed a three-point system, collapsible steering column, softer dashboard knobs, a door lock override controlled by the driver, head restraints, emergency flashers, along with a padded dash, and instrument panel. Dodge suspected that many young people might be trying to convince their parents to purchase the new Demon 340 and wanted to install components that might convince adults that the Dodge was safer than most cars on the road at the time.

The Value Of The Demon 340

Due to their limited number, the Dodge Demon 340 is a popular car collectible and can be found reasonably priced. Most Dodge Demon classic cars can be purchased through auctions for around $42,000, according to Hagerty. This makes it one of the more affordable classic cars to add to your garage.

The Specs of the 1971 Dodge Demon

1971/’72 Dodge Demon 340 Spec
Production 1971 - ‘72
Production Numbers 10,098 (1971)
8,700 (1972)
Engine Displacement 5.6L (340 ci)
Horsepower 275 hp
240 hp (1972)
Torque 340 lb-ft
Compression 10.5:1 (1971)
8:4:1 (1972)
Carburetion 4 bbl
Valves 16 valves
Firing Order 1- 8 - 4- 3 - 6 - 5- 7 - 2
Block Material Cast iron
Cylinder Head material Cast iron
Timing chain Double roller timing chain
Weight 3,353 lbs
Length 192 inches
Width 71.6 inches
Height 53 inches
0 - 60 mph speed 7.5 seconds
Quarter Mile Time 14.49 seconds @ 98.25 mph
Top Speed 128 mph
Dual Exhausts Yes