The most noticeable change on the '71 'Cuda was the front-fender air extractors, or gills. The base 383, the 440, and the Hemi were all still available (as were Shaker hoods), but with downgraded horsepower ratings for the 383 and 440. By 1972, big-block 'Cudas were gone. What was left of the 'Cuda was a hardtop 340 car with an 8.5:1 compression ratio.

Duster 340Following in the footsteps of the Road Runner in terms of budget performance was the Duster 340. It not only fit into Plymouth's RTS theme of performance for the masses, but also stood as a direct competitor to the Chevy Nova SS and Dodge Dart Swinger 340. Though it was pieced together with little fanfare, the Duster was an enormous success.

The Valiant body was streamlined to resemble a fastback style. The dual black stripes on the side and rear, as well as that big 340 badging on the hood, gave the Duster 340 a unique look. The tornado detailing on the rear also provided a signature for the model and kept in line with the success of the Road Runner's cartoon styling. A rear spoiler was optional but seldom ordered. The 340 was hooked up to a standard three-speed tranny and an 831/44 rearend.

Plymouth maintained its commitment to suspension strength throughout the RTS lineup, and the '70 Duster 340 included high-rate torsion bars, rear springs, shock absorbers, and front antisway bars. Unique to the Duster 340 were the 511/42-inch wheels, which came standard with front disc brakes. Even though it was the least expensive model in the RTS lineup, it was also the lightest weight and had 14-second capability.

The interior was plain to begin with. But, options like bucket seats, elongated center console, Tuff steering wheel, light package, color-keyed carpet, pedal dress-up, and Day/Nite mirror could spruce things up quickly. The instrument panel was taken from the '69 Barracuda and featured the Rallye instrument cluster, with a small tachometer between the two main instrument binnacles.

The '71 Duster 340 was fitted with full-length 340 side stripes, and optional was the "340 Wedge" hood detailing. Another new option was the plaid/vinyl interior. Plymouth advertisements in 1971 featured the Duster 340 with the new Duster Twister, a downsized version of an already economical car. The Twister carried a 318 V8 or Slant Six. While it was not part of the RTS, with the 340 grille, side stripes, racing mirrors, and a scooped hood with strobe stripes, it still looked the part of musclecar.

The '72 Duster 340 was rated at just 240 hp, but it was upgraded to an electronic ignition and, on the outside, was given a tornado cartoon on the side stripes.

GTX and Sport Fury GTBilled by Plymouth as the "Executive Branch" of the RTS group, the GTX and Sport Fury GT represented the more expensive end of the economy performance market. This tandem of 440 cars was marketed less toward youths and more toward the young family demographic-roomy, yet sporty, with a restyled nose and rear for the '70 GTX. Based on the Belvedere body, the '70 GTX featured a base 440 with a single four-barrel Carter AVS carb. While it was only available in a hardtop, the '70 GTX offered upgrades to a 440 Six-barrel and 426 Hemi engine. The '70 Hemi came with a hydraulic-lifter camshaft for improved emissions, and the GTX breathed through the open-close Air Grabber hoodscoop, which was standard on the Hemi and optional on the 440s.

Extra-heavy-duty torsion bars and front stabilizer bars helped support the big GTX body. All '70 GTXs were equipped with 14x6 wheels, while the larger Sport Fury GTs came standard with 15x6 rims. Both the GTX and Sport Fury GT came with 831/44 rears, although a four-speed GTX got a 931/44. The GTX came standard with side stripes, and a triple hood stripe could be ordered to match.