What was the fastest Impala?
The fastest production Impala was the 1969 Chevrolet Impala SS equipped with a 427 cubic inch V8 delivering about 425 horsepower. In stock form, it could reach roughly 140 mph and accelerate from 0 to 60 mph in the mid‑6‑second range. This article places that claim in historical context and compares it with other fast Impalas from the era.
Historical context: the rise of Impala performance
In the 1960s, GM’s full-size Chevrolets embraced big-block power as a defining feature. The Impala SS (Super Sport) became the performance-focused variant, leveraging high‑displacement V8 engines such as the 409 and later the 427. As horsepower rose, so did the Impala’s straight‑line speed, making the late-1960s SS models the most sought‑after for performance enthusiasts.
The SS 427: specifications and performance
Below are the core specifications that establish the 1969 Impala SS 427 as the benchmark for speed in the model’s history.
- Engine: 427 cubic inch V8 (7.0 L) rated at about 425 horsepower (advertised gross rating at the time) with torque around 460 lb-ft.
- Drivetrain and transmission: Rear‑wheel drive; available with a Muncie 4‑speed manual or Turbo-Hydramatic 400 automatic.
- Performance: 0–60 mph roughly in 6.5–6.7 seconds; top speed commonly cited around 140 mph, varying with gearing, tires, and other options.
- Notable characteristics: Hefty curb weight and robust acceleration, making it one of the era’s most recognizable performance Chevys.
These figures reflect stock configurations from the late 1960s; real‑world results could vary based on equipment and condition.
Other fast Impalas in the era
In addition to the 1969 SS427, several other Impalas from the early to mid‑1960s offered impressive performance thanks to the big‑block 409 and related SS packages. The following list highlights notable examples and their typical performance characteristics.
- 1963–1964 Impala SS 409: 409 cubic inches with horsepower commonly around 425 in higher configurations; top speeds generally cited in the 130–140 mph range, depending on gear and tires.
- 1967–1968 Impala SS 427 variants: 427 cubic inches with power outputs often listed near 390–425 hp depending on year and rating system; top speeds typically in the mid‑130s to around 140 mph with proper gearing.
Overall, while the 409-powered Impalas were blisteringly quick for their time, the 1969 SS427 is widely regarded as the peak of factory horsepower and top speed in the production Impala lineup.
Summary
The Chevrolet Impala’s fastest factory model was the 1969 Impala SS 427, driven by a 427 cu in V8 delivering about 425 hp. It achieved top speeds around 140 mph and 0–60 mph in the mid‑6‑second range, depending on options and gearing. While earlier 409‑powered Impalas offered exceptional performance, the 427‑powered SS427 represents the era’s speed apex for the production Impala, with later variants generally not matching its horsepower‑per‑pound figure on the street.
