Significant engineering changes were introduced for 1964, while the model lineup and styling remained relatively unchanged. The engine displacement was increased from by an increase in stroke. The base engine power increased from , and the high-performance engine increased from . The Spyder engine rating remained at despite the displacement increase of the engine. In 1964, an improvement in the car's swing axle rear suspension occurred with the addition of a transverse leaf spring along with softer rear coil springs designed to diminish rear roll stiffness and foster more neutral handling. Spring rates could now be softer at both ends of the car compared to previous models. The heavy-duty suspension was no longer optional, although all models now had a front anti-roll bar as standard. Brakes were improved with finned rear drums. The remaining pickup, the Rampside, was discontinued at the end of the model year.