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50 Years of Police Impala

Written by PFM Staff

The small block V-8, practically the same as we know it today, was introduced in 1955. That same year, the full-size Chevrolet was drastically remodeled. It also got a ball joint suspension new ladder frame, 12-volt electrical system and wrap-around, one-piece windshield. The 1955 small block V-8 pushed the new Chevy into the Cadillac and Chrysler performance category, and far ahead of its Ford and Plymouth competition.

This was also the year Chevy introduced its police package. Since it was a mid-year release and had such a long lead time, 1956 is really the first true year for the formal police package. Dodge also introduced a police package in this year. Ford had offered a formal police package since 1950. These 1955, 1956 and 1957 Chevys have gone on to be classics.

The First Impala
In 1958, Chevy totally redesigned its full-size car. The company gave it a brand new X-frame, 4-wheel coil spring suspension, a longer wheelbase and Chevy’s first big block V-8: the 348ci W-block. This would grow up to be the famous 409ci big block. “She’s so fine, my 409.” For use in police cars, the 348ci V-8 was available with a single 4-bbl carburetor or with three 2-bbl carbs.

To go with its totally new sedans, in 1958 Chevy also went with totally new car names. The One Fifty became the Delray. The Two Ten became the Biscayne. The Bel Air name remained unchanged. And a new, high-end Bel Air sub-series was introduced: Impala. The Impala name originated from a 1956 Corvette concept show car.

The 1958 Chevy was longer, lower, wider…and heavier. In fact, the 1958 was so much heavier than the 1955-1957 Chevys that the mostly carryover brakes just couldn’t keep up. The police Chevy even got 15-inch wheels for brake cooling, while the retail cars all used 14-inch wheels. And the extra performance from the new big block engine just made this situation worse. As a result, one of the best looking cars from the 1950s carries this “under-braked” reputation to this day.

All that changed for 1959. Zora Arkus-Duntov, the Corvette’s chief engineer, developed an entirely new braking system for the even longer and heavier 1959 police model. This car used larger drums with cooling fins, 25% more lining area and for the first time, sintered metallic linings. This was the forerunner of today’s semi-metallic brake pads.

The 1959 Chevy reached “big car” status with its new 119-inch wheelbase but still could not be bid to most state police and highway patrols. They specified a 122-inch wheelbase. The police Chevy remained powered by a variety of 6-cylinder, small block V-8s and big block V-8s with minor sheet metal changes until 1962.

In that year, two of Chevy’s most famous engines were put in police cars: the 327ci small block and the 409ci big block. In dual 4-bbl form, the 409ci V-8 was the only official police engine of any make or year to produce over 400 hp. It produced 409 hp. “Giddy up, giddy up, 409.”

In 1965, the big Chevy was greatly restyled, got the “porcupine head” 396ci big block and the legendary Turbo HydraMatic transmission, finally replacing the lame 2-speed Powerglide. The 396ci engine grew to 427ci for 1966. For 1967, front disc brakes were introduced on Chevy police cars.

In 1969, the most popular powerplant in Chevrolet history was introduced. The 327ci small block was stroked slightly to become the famous “350.” In 1970, the 427ci V-8 was stroked to become Chevrolet’s largest ever police engine: the 454ci V-8. The big Chevy started to gain weight in 1969 and put on weight every year through 1976. In 1971, the wheelbase was bumped to 121.5-inches. The 1971 to 1976 models were the largest, longest and heaviest sedans ever built by Chevrolet.

For 1977, the big Chevy underwent the biggest change since the 1958 X-frame sedan became the 1959 B-body. The wheelbase was shortened to a mere 116-inches, where it would stay for 20 years. The big sedan shed 660 pounds, and all the big block police engines and small block engines over 350ci were history.

Proving once again that it is the power-to-weight ratio that matters, and not engine size alone, the 1977 Impala with the 350ci V-8 had the same acceleration as the 1976 Impala with the 400ci V-8. That didn’t matter. The major state police and highway patrols shunned the small block-powered Chevy as long as big block Fords, Dodges and Plymouths were available. These other marques would both be downsized and lose their big block V-8s after 1978.

From 1977 to 1990, the big Chevy didn’t change much. The Chevy police sedan continued to be powered by the 350ci V-8, and vehicle performance was bleak. Top speeds were under 120 mph. A few subtle changes took place. The 1980 Impala lost another 100 pounds thanks to an increased use of aluminum and thinner, high-strength steel. For the first time ever, a V-6 engine powered a full-size Chevy: the 3.8L V-6.

In 1983, the 4-speed overdrive automatic with a lockup torque converter was introduced on Chevy police cars. In 1985, the 4.3L V-6 police engine got fuel injection. The 350ci V-8, now frequently called the 5.7L V-8, went to fuel injection in 1989. For 1986, the Impala nameplate was dropped in favor of the new name, Caprice.

A major styling change took place for 1991. The “aero” styling with its semi-closed rear wheelwells inspired many jokes and much ridicule. But the joke was on the competition: the restyled Chevy now hit 130 mph for the first time in decades. This was also the first year for the anti-lock braking system, ABS. Police officers all over the country underwent special training in how to brake with ABS. The driver’s side airbag was also introduced in 1991.

While Chevy opened the rear wheelwells for 1993, promptly ending the styling jokes, the big change took place in 1994. That was the year the Caprice received the Corvette’s 5.7L “LT-1” V-8, the 4L60-E electronic 4-speed trans, 4-wheel disc brakes and dual side airbags. The 1994 to 1996 Chevy Caprice with the 5.7L LT-1 engine remains one of the most popular police cars of all time. More than a decade after the Caprice was discontinued, the most common question fielded by GM Fleet personnel remains, “When are you going to bring the Caprice back?”

For the three model years after 1996, Chevy continued to quietly tweak its front-wheel drive, V-6-powered Lumina sedan. In 2000, the company released the new Impala, a different sedan from the otherwise reliable Lumina, and a much different sedan from the old Impala. The new police sedan, of course, is FWD and V-6 powered. However, the late-model versions are just as fast around a road racing course, have the same acceleration to 100 mph and have a higher top speed than today’s dominant RWD and V-8-powered sedan.

With an economical, variable valve timing engine that runs on E85 and 140 mph top speeds, the new Impala has a police fleet maintenance record—and both ownership costs and operating costs—that rivals the best. That shouldn’t be a surprise. The 2008 Impala has 50 years of police experience!