The 1967 Chevrolet Impala represents a pinnacle of American muscle car engineering, specifically regarding its potent powertrain options. During this era, Chevrolet offered a hierarchy of performance that allowed buyers to tailor the Impala to their specific need for speed. Understanding the 1967 Impala horsepower figures requires looking beyond the base model to the top-tier SS427 and the legendary COPO variants. This year marked the final full model year for the first-generation Impala, making its performance specifications historically significant.
Base and Mid-Level Performance Options
For the majority of Impala buyers in 1967, the focus was on comfort and style rather than outright speed. The standard powertrain provided adequate power for daily driving, but performance enthusiasts had clear paths to upgrade. The base V8, while not a powerhouse by today's standards, was a reliable workhorse. Buyers seeking more could step up to the 327 cubic-inch V8, which formed the core of the performance lineup. This engine was available in several states of tune, creating a spectrum of power outputs that served as the foundation for the top-tier offerings.
327 V8 producing 250 horsepower
327 V8 with high-output specs approaching 300 horsepower
Available manual and automatic transmissions for versatility
The Introduction of the SS427
The true head-turner for 1967 was the Super Sport 427, or SS427. This package transformed the Impala into a serious performance machine, slotting it between the intermediate Chevelle SS396 and the full-size Caprice. The SS427 was not merely a trim level; it was a commitment to brute force, signified by its massive hood scoop and aggressive styling. This model was aimed squarely at the consumer who wanted a factory muscle car that could dominate on the street or the strip.
Decoding the 427 Cubic-Inch Engine
The "427" in the name refers to the 427 cubic-inch V8 engine, specifically the Mark II version. This was a large-displacement motor designed to produce immense torque and horsepower. Unlike smaller engines, the 427 was built to handle high RPMs and deliver a violent acceleration curve off the line. The engineering focus was on creating a powerplant that could outperform competitors from Ford and Chrysler in the emerging muscle car wars.
Horsepower Ratings and the COPO Option
General Motors had a policy in place that limited factory horsepower ratings to a conservative 1 HP per cubic inch, which would put the 427 at 420 horsepower. However, Chevrolet engineers found a way to bypass this restriction for racing purposes. The Central Office Production Order, or COPO, was a dealer ordering system initially for NHRA and NASCAR teams. The COPO 9561 and 9563 packages brought legendary engines to the public. The L72 variant, rated officially at 425 horsepower, was capable of producing over 450 horsepower in race trim. The L88 variant, arguably the most desirable, was conservatively rated at 430 horsepower but was a high-revving, race-bred monster capable of exceeding 500 horsepower.
SS427 L72: Rated at 425 HP / 460 lb-ft torque
COPO 9561 (L72): Officially 425 HP, capable of 450+ HP
COPO 9563 (L88): Rated at 430 HP / 460 lb-ft torque
