Chevrolet Impala

The Chevrolet Impala is a sedan-based automobile developed and built by the Chevrolet car division of General Motors. Ed Cole, Chevrolet's chief engineer in the late 1950s, defined the Impala as a "prestige car within the reach of the average American citizen."

Pre-1958

The Impala was originally a Corvette-based prototype car in the early to mid-fifties. Many Chevrolet models originated as Corvette-based experiments; examples include the Corvair and Nomad. The Impala originated as a sports coupe, and was the least Corvette-like of the few because it wasn't introduced with the originals.

1958-1972

The Impala was introduced in 1958 as a new up-level, sporty trim package created for Bel Air coupes and convertibles. Unique to the model were its six taillights, a classic styling cue that became its trademark. It was named for a southern African antelope. The Impala became a separate model in 1959 in both two and four-door versions and became the best selling car in the Chevrolet product line. For 1960, it became the best-selling automobile in the United States and held that position for the next decade. From 1958 until 1996, Impala sales were in excess of 13 million units, more than any other full-size car in the history of the automobile. In 1965, the Impala set an all-time industry annual sales record of more than 1 million units, which has never been bettered.

The Impala is often credited with starting the muscle car era. In the 1960s, gasoline was cheap and consumer demand for power exceeded the need for efficiency. Buyers were clamouring for as much room, performance, amenities and quality as they could get for their dollars. In 1961 the first true muscle car was introduced with the Impala SS (Super Sport). The SS badge was to become Chevrolet's signature of performance on many models. The SS package in 1961 was truly a performance package. Nothing less than the high-performance 348 in³ (5.7 L) engines or the new 409 in³ (6.7 L) could be ordered. The 348 options were 305, 340 and 350 hp (230, 255 and 260 kW) engines. It consisted of upgraded tires on station wagon wheels, springs, shocks and special sintered metallic brake linings. The Impala SS could be identified by SS emblems on the rear fenders and trunk lid. The Impala SS became its own series (separate model rather than an option package) for 1964. A 1967 Chevy Impala was the focus of a debunked Darwin Award in the JATO Rocket Car story.

1973-1985

The 1970s showed a change in the American view of the automobile. The impact of the 1973 oil embargo on the industry was dramatic. Gasoline prices doubled between 1973 and 1979. Industry car sales plummeted 20 percent between 1973 and 1974, and for the first time in recent history, annual passenger car travel in the U.S. actually went down. This change in the automobile market resulted in Chevrolet redesigning the Impala once again in 1977 to meet changing demands. The new Impalas were shorter in length, taller in stature and narrower. The Impala embodied the new image of the full-size American car - smaller, lighter, more efficient. For example, even with its trim dimensions, the new Impala featured increased headroom, legroom and trunk space. Production of the downsized model actually increased in 1977 versus a year prior.

Engines:

• 1978-1985 350 5.7 L (350 in³) V8

• 1985 4.3 L (262 in³) V6

1994-1996

In 1991, the GM B platform was extensively redesigned, though it retained the same shortened frame design of the 1977 redesign.

The Impala SS badge was resurrected at the 1992 Detroit Auto Show as a concept car designed by GM designer Jon Moss. The concept car was two inches lower to the ground than the regular Caprice, and was powered by a 8.2-liter (500 cu in) engine. Eventually, the concept car's engine was replaced with a 5.7-liter (350 cu in) engine derived from the Corvette in order to show the public what would be offered if put into production (an off-road specification 510-cubic-inch (8.4 L) V8 was eventually put into the engine bay of the prototype years later).

The 1994 Impala SS went into production 14 months later at GM's plant in Arlington, Texas, and was almost identical cosmetically to the concept car, the only noticeable change being the chromed bowtie logo on the grill (vs a red logo on the concept). The car was, in essence, a high-performance version of the Caprice. From a mechanical standpoint, it used the Caprice 9C1 police package as its base and as such got most of the equipment formerly available only to law enforcement and government agencies. This included a sport-tuned suspension with reinforced shocks and struts, a high-capacity upgraded reverse flow cooling system, larger and more powerful four-wheel disc brakes, transmission cooler, dual exhaust, a higher-output electrical system, and other minor mechanical alterations. Not all of the police equipment was carried over however, as the Impala SS did not get the external oil-to-air engine oil cooler, nor were all the body mounts secured (the standard Caprice and Impala SS were assembled at the factory with the front 3 body mounts missing one of the rubber cushions, while the 9C1 was assembled with all rubber cushions in place), although both are popular aftermarket additions to the Impala SS by their owners.

The Impala SS was uniquely fitted with a standard 3.08 gear. The limited-slip rear differential was standard (as opposed to the option G80 on caprices) and suspension that was an inch lower. A retuned LT1 5.7-liter (350 cu in) small-block V8 was standard on the Impala SS, making 260 horsepower (190 kW) and 330 pound-feet (450 N·m) of torque (retuned from the prototype's 300 horsepower (220 kW) rating). The primary difference between the LT1 in the Impala and the LT1 that was in the Corvette and Camaro was that the Impala engine was fitted with cast-iron cylinder heads instead of aluminium ones, and a camshaft that was designed more for low-end torque than high-end horsepower. Another difference was that the Impala LT1 had 2 bolt main bearing caps while the Corvette LT1 had 4 bolt main bearing caps. The transmission used in the car was the 4L60E, which was itself an upgraded and revised version of the previous 700R4. However, the transmission was not beefed up for the power of the LT1, and transmission failures after 100,000 miles (160,000 km) were commonplace.

Several other cars in the B-body line also shared a similar power train: these were the Chevrolet Caprice, Buick Roadmaster, and the Cadillac Fleetwood which all shared the LT1 engine and 4L60E automatic transmission.

Cosmetically, the Impala SS received body-colored trim, which helped reduce the sometimes "bloated" look of the standard Caprice, a unique single-bar grille with no hood ornament and, a rear deck spoiler. It was fitted with 17-inch (430 mm) brushed aluminum wheels with 255/50ZR17 tires. Inside, the car came with a central console with cup holders (1994 and 1995 models) and a storage compartment, leather seats embroidered with the Impala SS logo, and a standard leather-wrapped steering wheel.

For the 1994 model year, it was available only in black with a grey interior. Due to a shortage of the unique 5-spoke aluminum wheels (manufactured by ROH in Australia), only 6,303 cars were sold. However, the wheel shortage was remedied for the 1995 model year and 21,434 cars were sold. In 1995, Dark Cherry Metallic and Dark Grey Green were added as exterior colour options, and the body panelling on the rear quarter panel was altered to reflect the cosmetic effect formerly achieved by a window insert. 1996 was the last year of production with 41,941 units sold. The 1996 Impala SS production went late into the model year; some being produced as late as December 17, 1996. It saw minor interior alterations, with the digital speedometer being replaced by an analogue one, along with a tachometer. The shifter was moved from the column to the center console, and the engine was given an OBD-II computer control system (the camshaft was reground to adjust for the new computer).

The entire B/D-body line, consisting of the Chevrolet Caprice, Impala SS, Buick Roadmaster and Cadillac Fleetwood, was discontinued by General Motors, as GM wanted more assembly lines to be able to produce more profitable SUVs. Another fact was that the Caprice was the only B-body with a market share since fleet sales to law enforcement outnumbered sales of all other B-bodies.

2000

The Impala name was resurrected for the 2000 model year as a midsize 4-door sedan to replace the Lumina. Unlike the earlier Impalas, this one was front wheel drive and was only available with a V6. A new Impala SS with a supercharged V6 was brought out for the 2004 model year. Unlike the Lumina, the Impala was also used for most police cars.

Engines:

2000-2004 3.8 L (231 in³) V6

2000 3.1 3.1 L (191 in³) V6

2000-2002 LA1 3.4 L (207 in³) V6

2006

The 2006 Impala was introduced at the 2005 Los Angeles Auto Show. The base engine is a 3.5 L V6 producing 210 hp. The most notable news about the model, though, is the SS model's use of the Generation IV small-block V8 in a front wheel drive car for the first time: The new 5.3 L V8 (with Displacement on Demand) will produce 303 hp. The car is 200.4 in (509 mm) long, 58.7 in (149.1 mm) high, and 72.9 in (185.2 mm) wide.

Engines:

3.9 L LZ9 V6, 240 hp (179 kW)/245 ft·lbf (332 N·m)

3.5 L LZE V6, 210 hp (157 kW)/220 ft·lbf (298 N·m)

5.3 L LS4 V8, 303 hp (226 kW)/323 ft·lbf (438 N·m) (SS)