What engine was in the 1968 Plymouth GTX?
Two big-block V8s were available: a 426-cubic-inch Hemi and a 440-cubic-inch Magnum.
Engine options for the GTX
The GTX, Plymouth’s performance-oriented version of the Belvedere, offered two high-powered V8s in 1968. The 426 Hemi was the top-tier choice, famous for its raw power, while the 440 Magnum provided a robust alternative with strong performance and broader availability.
426 cubic inch Hemi V8
The 426 Hemi was the pinnacle option for the GTX. It delivered about 425 horsepower (gross) and roughly 490 pound-feet of torque, giving the car exceptional acceleration and top-end punch. Because of its power, the Hemi setup was relatively rare and highly prized among collectors.
- Displacement: 426 cubic inches (7.0 L)
- Power: ~425 horsepower (gross)
- Torque: ~490 lb-ft
- Availability: optional on the GTX in 1968; limited production
In short, the Hemi-equipped GTX represented the apex of 1968 performance, combining the Hemi’s distinctive design with the model’s mop-up power.
440 cubic inch Magnum V8
The 440 Magnum was the more widely available option and became the workhorse engine for many GTX buyers. It generally produced around 375 horsepower (gross) with substantial torque, offering strong straight-line speed without the premium cost of the Hemi.
- Displacement: 440 cubic inches (7.2 L)
- Power: ~375 horsepower (gross)
- Torque: ~480 lb-ft
- Availability: widely available option on GTX in 1968
For most GTX customers, the 440 Magnum strike a balance between performance and affordability, contributing to the model’s reputation for brutal acceleration.
Summary
In 1968, the Plymouth GTX could be equipped with two big-block engines: the 426 Hemi and the 440 Magnum. The Hemi stood as the high-performance crown, while the Magnum offered strong, more accessible performance. Together, these options defined the GTX’s legacy as a premier muscle car of the era.
