Plymouth was in a tough spot in 1970. Their Valiant-based line of A-Bodies was without a sporty coupe, as the performance-bred Barracuda had jumped platforms to the new E-Body ponycar line. Without the youth appeal of a sporty vehicle to compete directly with the venerable Chevrolet Nova, Plymouth scurried to introduce the all-new Duster. Small, nimble, and sharing the same underpinnings as the previous A-Body models, the Duster and its bug-eyed Tornado cartoon character became the newest darling of the Plymouth performance line. Still, with only a 108-inch wheelbase, the Duster featured flashy packaging, the familiar Valiant grille, and a long, swooping rear C-pillar that would predate the B-Body redesign the following year. In fact, most of the Duster would consist of carryovers from the Valiant model since the development of the Duster was a clandestine operation. Plymouth snuck the Duster model underneath corporate's noses, taking a $15 million gamble. Their bet paid off in spades; the Duster's sales shot far above the more angular and austere Dart.

Knowing their sibling had bested them, Dodge opted for a similar A-Body model the next production year-the Duster-inspired Demon. Just as the Duster shared most of its components with the Valiant, the Demon drew inspiration from the Dart line-front clip, cowl, front and rear bumpers, quarter-panel inserts, and other interior accents. But the Demon was doomed from the beginning. Duster sales barely squirmed when the Demon hit showroom floors, and advocates for the religious right began to lament that Dodge's cherubic devil with his pitchfork was "sacrilegious" and "highly offensive." Internal politics within Chrysler made the environment dicey as well. Dodge felt burned by Plymouth's Machiavellian plotting and demanded not only that Plymouth share the Duster designs but also introduce a vehicle based upon the Dart Swinger. Plymouth begrudgingly agreed and introduced the Scamp.

The Demon moniker would only last two years: 1971 and 1972, when the coupe would be retagged the Dart Sport. But the Demon with its particular flair and style, along with its performance packages, made for an appealing, albeit controversial, muscle machine.

Karns City, Pennsylvania's Greg Thorhauer is a man of very few words, letting his Demon do the talking. The '93 Viper Red A-Body was at the '06 Chryslers at Carlisle show, and caused Mopar Muscle's photographer-for-hire, Jerry Heasley, to take a second glance. Greg's wife Shannon tells the tale of how the Demon became a regular fixture at their home. "The [Demon] was originally owned by a gentleman serving in the Navy. While he was driving to his base in Norfolk, Virginia, in the Demon, he stopped by our neighbor's house to look at a '68 Dodge Charger that was for sale. [Greg] approached him and asked if his Demon was for sale. His reply was, 'Everything is for sale.' [Greg] attempted to make a deal with him right then, but he was on his way back to the base."