The Plymouth GTX (1967-1971) was introduced as the Belvedere GTX in 1967 by the Plymouth division to be a "gentleman's" muscle car.
The 1970 GTX received a major redesign but sales still suffered. Stylists made the lines smoother, and a "power bulge" hood was introduced, as well as non-functional rear brake air scoops. The convertible model was dropped in 1970. The Air Grabber hood was brought back, 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 4 barrel, as well as the 440+6 barrel (three two barrel carburetors) and the 426 Hemi. The 440+6 could compete closely with the Hemi, up to highway speeds. In keeping with the GTX marketing strategy, the 1970 model included many standard features. The only other Plymouth luxury/performance model was the full-size Sport Fury GT, built on the C-Body platform. The GT was added to the lineup in 1970. The GT received nowhere near the recognition of the GTX, even though they shared many performance features. The Sport Fury GT was the full-size member of The Rapid Transit System. The Sport Fury GT was often viewed as more of a mature gentleman's performance luxury car.
Source: Wikipedia, 2011; Mecum Auctions