Horsepower ratings define the legacy of the Chevrolet Impala Super Sport, stretching from early 1960s muscle blocks down to front-wheel-drive final iterations, Jalopnik reported.
The retail version of the Impala SS from the 1960s produced up to 425 horsepower across its first two generations. Later generations from the 1990s and 2000s offered between 240 and 303 hp.
Output figures for 1960s Impala SS models reflected gross horsepower ratings that generally omitted intake, exhaust, and accessory loads. By the 1972 model year, Detroit switched to net horsepower calculations to reflect real-world engine configurations.
Rankings take into account the highest advertised horsepower ratings for regular-production SS models. Special race versions and modified cars are excluded from the figures.
Early Generations Reach 425 Horsepower
The 1961-1964 Chevrolet Impala SS launched in its third generation with 348-cubic-inch V8 units rated at 305, 340, or 350 horsepower, alongside a 360-horsepower 409-cubic-inch V8. In 1962, that powerplant received dual four-barrel carburetors to reach 409 horsepower.
Solid lifters, dual exhausts, and an 11:1 compression ratio pushed the 409 output to 425 gross horsepower for the 1963 model year. The 1964 Impala SS continued with that same 409 engine.
The 1965-1969 Chevrolet Impala SS matched that 425 peak output through a different path. Chevy launched a new Impala with a perimeter frame that helped the 1965 model sell a record 1,046,514 units, with roughly 23% built as SS variants.
For the SS, Chevy offered the L78 396-cubic-inch V8 rated at 425 gross horsepower. The L72 427-cubic-inch V8 joined the options list a year later with 425 hp, featuring a forged crankshaft and pistons, solid lifters, and a dual exhaust system.
The SS 427 continued into 1967 and 1968 using the L36 engine rated at 385 hp. Output increased to 390 hp in 1969.
The 5.3-Liter LS4 V8 Replaced the Supercharged V6
The final 2006-2009 Chevrolet Impala SS generated 303 hp as the most powerful modern generation. The supercharged V6 from the previous eighth-generation SS was replaced by a naturally aspirated 5.3-liter LS4 V8.
That engine delivered a zero-to-60 mph time of 5.6 seconds. The ninth-generation Impala SS used a front-wheel-drive layout with a heavy-duty four-speed automatic transmission.
In a 2006 road test, Car and Driver stated, “The SS seems to have been created to produce impressive numbers on paper with little regard to driver enjoyment.”
The 1994-1996 Chevrolet Impala SS used a rear-wheel-drive platform underpinned by the full-sized Caprice. A 260-horsepower 5.7-liter V8 engine produced 330 pound-feet of torque.
The vehicle weighed about 4,300 pounds and ran from zero to 60 mph in seven seconds. Chevrolet added an upgraded suspension, improved cooling, larger disc brakes, and a limited-slip differential.
The short-lived 2004-2005 Chevrolet Impala SS produced 240 horsepower from a 3.8-liter Series II engine with an Eaton supercharger. Zero-to-60 mph acceleration took 6.5 seconds.
| Generation | Model Years | Max Horsepower | Engine Type |
|---|---|---|---|
| Third / Fourth Gen | 1961–1964 | 425 hp (Gross) | V8 (up to 409 cu in) |
| Fifth Gen | 1965–1969 | 425 hp (Gross) | V8 (up to 427 cu in) |
| Ninth Gen | 2006–2009 | 303 hp | 5.3L LS4 V8 |
| Seventh Gen | 1994–1996 | 260 hp | 5.7L LT1 V8 |
| Eighth Gen | 2004–2005 | 240 hp | 3.8L Supercharged V6 |
Low-mileage 1996 Impala SS examples still hold strong collector appeal.
