The GTX came standard with a 440-cubic-inch (7.2-liter) RB-block V8 rated at 375 horsepower. In 1970, Plymouth also offered a six-barrel version of the 440 engine, which came with 390 horses on tap.

In the Dec. 1967 issue, Motor Trend published a comparison test of several of the supercar models that were all-new or substantially revised for the 1968 model year: GTO, Charger, GS 400, Torino ...