This Pontiac was the first of the 1960s muscle cars. With a 389 cubic-inch V8 that was similar to the 1960 NASCAR engine, the 1964 Pontiac Tempest Le Mans GTO was the forerunner of the muscle car formula: Dropping the largest engine into the smallest-bodied vehicle equals high performance. 

The 1964 Pontiac GTO breaks down like this – Le Mans is the top trim level of Pontiac's midsize car, the Tempest, with the GTO option. Styling of the GTO was similar to Pontiac's larger, successful, and cool-looking Grand Prix model. The GTO was available as a two-door coupe, hardtop, or convertible. 

The GTO started with the 389 block that was also used in the Grand Prix and added the heads from the larger 421 H.O. engine. A high-lift camshaft and specific hydraulic valve lifters were also added. The compression ratio was 10.4:1, which required premium gas. When combined with three two-barrel Rochester carburetors, known as the Tri-Power engine, this mill put out 348 horsepower and a stump-pulling 428 lb-ft of torque. Of the 32,450 Tempest Le Mans GTOs sold, only 8,245 had the Tri-Power. 

The GTO package included features that provided a balance of straight-line performance and cornering ability. GTOs had a stiffer suspension with upgraded shocks, and a thicker front anti-roll bar, wider wheels with low-profile, high-performance tires, and an upgraded clutch on manual-transmission cars. The transmission options included a three-speed manual, either a wide- or close-ratio four-speed manual, or a two-speed automatic.