The GTX was based on the Belvedere, and was differentiated by a blacked out grille and special rear fascia, fiberglass simulated hood scoops with optional racing stripes, a chrome "pop-open" fuel filler cap, and a tachometer mounted on the center console. The GTX was positioned as a "gentleman's muscle car". Standard was Plymouth's V8 engine called the "Super Commando 440" rated at. Optional was Chrysler's Hemi. A heavy dutysuspension system was also standard.
Performance
1968-1970
1968
Chrysler introduced major changes in the design of the 1968 model Plymouth B-bodies and the GTX was given a completely new look. A new hourglass body replaced the previous rectilinear design. The high performance 440 was standard in the GTX as was the TorqueFlite automatic transmission, while it was an extra cost option in the Road Runner. The GTX used the Sport Satellite trim and was offered in two body styles, a two-door convertible and a two-door hardtop. All featured dual horizontal "racing stripes" on the lower sides ending with a GTX emblem ahead of the rear wheel openings. The GTX was positioned to be an upscale model of the Plymouth Road Runner by adding luxury to performance. The new budget performance version of the Belvedere featured the new Chrysler RB engine#383| "Super Commando" V8. It also had less insulation and comfort items, which reduced weight and kept it in the low price field.
1969
In 1969, the GTX's sales dropped when the Road Runner was also offered in a convertible body style. The GTX received minor cosmetic changes to the tail lights and grille, as well as the side marker lights. An optional "Air Grabber" hood featured functional openings on both sides of the hood that were controlled from the dash. The 1969 GTX had standard black lower-body side paint in place of the previous stripes. The standard 440 V8 was still rated at. This was the last year that the convertible model was available on the GTX. Total production was 701 GTX convertibles in 1969. Of those, eleven were equipped with the 426 Hemi; four were 4-speeds and seven had TorqueFlite automatics.
1970
The 1970 GTX received a minor redesign with a new grille and rear taillights. Sales were low as the car did not look much different from the Road Runner. Stylists made the lines smoother, and a "power bulge" hood was introduced, as well as non-functional rear-brake air scoops. The convertible body style was no longer available. The Air Grabber hood returned, but instead of having two narrow openings running length-wise as in 1969, it had one opening scoop located on the power bulge. The GTX was available with the standard 440 four-barrel carburetor. Optional were the 440+6 barrel and the 426 Hemi. In keeping with the GTX marketing strategy, the 1970 model included many standard features. The only other performance luxury model in Plymouth's lineup was the full-size Sport Fury GT, built on the C-Body platform. The GT was added to the lineup in 1970.
1971
The B-body was redesigned for 1971 and featured rounded "fuselage" styling with a raked windshield, hidden cowl, and a loop-type front bumper around a deeply inset grille and headlights. This was the final year for the GTX as a stand-alone model. The convertible body style was dropped. Engine choices were 440 four-barrel, 440 with three two-barrels, and 426 Hemi. Emission restrictions such as lower compression ratios and faster-acting choke operation lowered the base 440 output by, to. The 440 Six Barrel was down to, but the Hemi was still rated at. Due partly to rising insurance rates on muscle cars, sales were low. There were less than 3,000 units produced in 1971. For 1972 through 1974, any Road Runner ordered with the optional 440 was renamed Road Runner GTX and included the badging of both previous models.
