The Plymouth GTX (1967-1971) was introduced as the Belvedere GTX in 1967 by the Plymouth division to be a "gentleman's" muscle car.
It was to be an exceptional blend of style and performance. What differentiated it from a normal Belvedere was its special grille and rear fascia, shared with the Satellite, as well as mock hood scoops, chrome "pit stop" fuel filler cap and optional racing stripes. For the performance aspect of the vehicle, a heavy duty suspension system was made standard. Standard too was Plymouth's 440 cu in (7.2 L) V8 called the "Super Commando 440". The engine was rated at 375 hp (280 kW). Buyers in 1967 could pay an extra US$546 and replace the 440 with Chrysler's 426 cu in (7.0 L) Hemi. The 426 was nicknamed the "Elephant."
Source: Wikipedia, 2011