vehical history

In the early Fifties, British bikes started gaining popularity in the American marketplace. Needing to offer a motorcycle that was lighter and faster than their 1200cc Big-Twins, Harley-Davidson introduced the sporty K Model. Although a four-year run may seem insignificant in the Motor Company's 100 year-plus history, a change from flathead to overhead valve design in 1957 turned the K-model into Harley's most successful selling motorcycle of all time, the Sportster.

In the early Fifties, British bikes started gaining popularity in the American marketplace. Needing to offer a motorcycle that was lighter and faster than their 1200cc Big-Twins, Harley-Davidson introduced the sporty K Model. Although a four-year run may seem insignificant in the Motor Company's 100 year-plus history, a change from flathead to overhead valve design in 1957 turned the K-model into Harley's most successful selling motorcycle of all time, the Sportster.

K-Model 1952-1953

The 'middleweight' K-series engine was based on the bottom end of Harley's 750cc side-valve W-series. Using the same 2-3/4" bore with a 3-13/16" stroke, displacement measured 45 cubic-inches. Compression ratio was 6.5 to 1. Cylinder heads were aluminum and finned to aid cooling. To save weight and space, the K series transmission was housed inside the rear of the engine cases, with a primary chain used to connect the crankshaft to a dry clutch. Unitized cases were new for the Motor Company, but English bikes such as the Vincent Black Shadow had used this design previously.

While the Big-Twin Harleys still ran a three-speed transmission operated by a left-hand tank-shift and foot-clutch, the K-model's four forward gears were shifted by the operator's right foot with a left-hand clutch lever. Gear-shift and drive-chain were on the right-hand side, with foot-brake on the left. This was done to compete in flat-track racing, and was opposite of what the Big-Twin Harleys were running.

Clearly the best handling Harley V-twin yet, the K-model's front forks were hydraulic, with a swingarm and twin shock absorbers used in the rear. This was the first time a civilian motorcycle produced by Harley-Davidson used hydraulic suspension on both wheels.

With a motor producing 30-horsepower on a bike weighing 400 pounds, first-year models were not much faster than Harley's 600-pound Big-Twin bikes. For 1953, H-D introduced the KK-model, which featured hotter cams and factory cylinder porting. Production total for 1952-1953 the K and KK-models was 3,693. Also this year, t he race-only KR-model started it's long and successful 16 years of production.

1954 KH and KHK Model

In 1954, the K was replaced by the larger-engine KH-model. Looking for inexpensive ways to increase power, Harley engineers upped engine displacement from 750cc to 883cc. This was achieved by lengthening engine stroke from 3-13/16" to 4-9/16". Cylinder jugs were made slightly taller to accommodate the new dimensions. Power was further increased by redesigned ports and bigger intake valves. To handle the extra power, the flywheel was redesigned and clutch enlarged from five disc to seven. Now producing 38 horsepower, top speed on a stock KH was 95 mph. The performance KHK-model featured higher-lift cams and polished ports.

1954 Golden Anniversary KH-Model

In the Fall of 1953, Harley-Davidson celebrated its 50th Anniversary in business. To commemorate this occasion, 1954 models displayed special medallions on the front fenders. Golden Anniversary KH's and KHK's were available in Pepper Red, Glacier Blue, Forest Green, Daytona Ivory, or Anniversary Yellow. If a customer so chose, gas tanks could be ordered in one color and fenders in another.

In 1955, a frame redesign included a lower seating position and shorter front fork tubes, both improving handling and giving the bike a sharper profile. To resolve problems caused by the increased engine torque, the rear wheel hub and spoke diameter were increased in size. A running change from 1954 saw revised engine cases having a trap-door, allowing access to the transmission without having to split the cases.

1956 KH-Model

Now offered in an array of colors, the K-Model was a sharp-looking bike. The older-style tail-lamps were replaced by more modern units from the Big-Twin Harleys. Frame and suspension improvements helped handling, but when compared to the OHV 500cc British Twins of the day, the K still lacked power. Increasing the engine size to 54 cubic-inches (883cc) had helped, but weight had also gone up. In 1956, a frame redesign had the engine mounted lower in the frame, and the backbone above the rear cylinder flattened. Arrival of a taller overhead-valve motor was apparent. The new OHV engine was fitted in 1957, and the K-series was renamed the XL Sportster.

Elvis Presley's Harley-Davidson KH Model

Elvis Presley was a motorcycle enthusiast, and in his lifetime owned a number of Harley-Davidsons. As a young star, Elvis' first Harley was a 1956 Pepper-Red KH-model. In May of that year, he appeared on the cover of the Motor Company's official periodical called 'The Enthusiast'. Harley-Davidson Motor Company presently owns the Enthusiast cover bike, which is believed to be the only Harley with a signed title in the name of Elvis Presley.

The 'middleweight' K-series engine was based on the bottom end of Harley's 750cc side-valve W-series. Using the same 2-3/4" bore with a 3-13/16" stroke, displacement measured 45 cubic-inches. Compression ratio was 6.5 to 1. Cylinder heads were aluminum and finned to aid cooling. To save weight and space, the K series transmission was housed inside the rear of the engine cases, with a primary chain used to connect the crankshaft to a dry clutch. Unitized cases were new for the Motor Company, but English bikes such as the Vincent Black Shadow had used this design previously.

While the Big-Twin Harleys still ran a three-speed transmission operated by a left-hand tank-shift and foot-clutch, the K-model's four forward gears were shifted by the operator's right foot with a left-hand clutch lever. Gear-shift and drive-chain were on the right-hand side, with foot-brake on the left. This was done to compete in flat-track racing, and was opposite of what the Big-Twin Harleys were running.

Clearly the best handling Harley V-twin yet, the K-model's front forks were hydraulic, with a swingarm and twin shock absorbers used in the rear. This was the first time a civilian motorcycle produced by Harley-Davidson used hydraulic suspension on both wheels.

With a motor producing 30-horsepower on a bike weighing 400 pounds, first-year models were not much faster than Harley's 600-pound Big-Twin bikes. For 1953, H-D introduced the KK-model, which featured hotter cams and factory cylinder porting. Production total for 1952-1953 the K and KK-models was 3,693. Also this year, t he race-only KR-model started it's long and successful 16 years of production.

1954 KH and KHK Model

In 1954, the K was replaced by the larger-engine KH-model. Looking for inexpensive ways to increase power, Harley engineers upped engine displacement from 750cc to 883cc. This was achieved by lengthening engine stroke from 3-13/16" to 4-9/16". Cylinder jugs were made slightly taller to accommodate the new dimensions. Power was further increased by redesigned ports and bigger intake valves. To handle the extra power, the flywheel was redesigned and clutch enlarged from five disc to seven. Now producing 38 horsepower, top speed on a stock KH was 95 mph. The performance KHK-model featured higher-lift cams and polished ports.

1954 Golden Anniversary KH-Model

In the Fall of 1953, Harley-Davidson celebrated its 50th Anniversary in business. To commemorate this occasion, 1954 models displayed special medallions on the front fenders. Golden Anniversary KH's and KHK's were available in Pepper Red, Glacier Blue, Forest Green, Daytona Ivory, or Anniversary Yellow. If a customer so chose, gas tanks could be ordered in one color and fenders in another.

In 1955, a frame redesign included a lower seating position and shorter front fork tubes, both improving handling and giving the bike a sharper profile. To resolve problems caused by the increased engine torque, the rear wheel hub and spoke diameter were increased in size. A running change from 1954 saw revised engine cases having a trap-door, allowing access to the transmission without having to split the cases.

1956 KH-Model

Now offered in an array of colors, the K-Model was a sharp-looking bike. The older-style tail-lamps were replaced by more modern units from the Big-Twin Harleys. Frame and suspension improvements helped handling, but when compared to the OHV 500cc British Twins of the day, the K still lacked power. Increasing the engine size to 54 cubic-inches (883cc) had helped, but weight had also gone up. In 1956, a frame redesign had the engine mounted lower in the frame, and the backbone above the rear cylinder flattened. Arrival of a taller overhead-valve motor was apparent. The new OHV engine was fitted in 1957, and the K-series was renamed the XL Sportster.

Elvis Presley's Harley-Davidson KH Model

Elvis Presley was a motorcycle enthusiast, and in his lifetime owned a number of Harley-Davidsons. As a young star, Elvis' first Harley was a 1956 Pepper-Red KH-model. In May of that year, he appeared on the cover of the Motor Company's official periodical called 'The Enthusiast'. Harley-Davidson Motor Company presently owns the Enthusiast cover bike, which is believed to be the only Harley with a signed title in the name of Elvis Presley.

history of automotif perfomance

History of Classic Cars, Trucks, and Motorcycles

If you're looking to find information on your favorite classic car, truck, or motorcycle, you've found the right place! Classic-Car-History provides in-depth articles and photos on all classic vehicles - muscle cars, sports cars, pony cars, exotics, trucks, and motorcycles, too. You'll find everything from flatheads of the Forties to the computerized and fuel-injected machines of the Eighties.

While you're here, take a minute to check out our gallery pages, which feature hundreds of large, high-resolution photos collected from car shows, garages, race tracks and parking lots all across America.

This site was written by motorheads for motorheads - enjoy!

History Of Automotive Performance

Shortly after World-War-Two, development of the modern overhead-valve V8 began. Automotive engineers were finding new ways to increase horsepower, and with better octane fuel available, higher-compression engines were now possible.

It was also at this time that new outlets for car performance started appearing, such as NASCAR oval tracks, Speed Trials at Florida's Daytona Beach, and straight-line acceleration runs at NHRA drag strips.

Oldsmobile was the first of the GM divisions to offer an OHV eight-cylinder engine, debuting their "Rocket V-8" in 1949. The 303-cid V8 featured a forged steel crank, aluminum pistons, and a dual-plane intake manifold, producing 135 horsepower and 263 pound-feet of torque. Once placed inside Oldsmobile's lighter-bodied 76-series cars, the Rocket 88 series began, which dominated NASCAR's Grand National series for several years. The Rocket 88 is sometimes cited as the first muscle car.

Recognized as one of the Top-Ten engines of the 20th Century, Chevrolet's small-block V-8 was first offered in 1955. Originally displacing 265 cubic-inches and netting 195 horsepower, the venerable motor would be offered in numerous displacements over the next four decades. Under the hood of a 1970 Corvette, the LT-1 350 small-block produced 370 horsepower. It's size, power capability, and easy maintenance helped the Chevy small-block become the most successful engine in Motorsports racing history.

Ford's answer to the Chevy Corvette was not a bare-bones sports car, but rather an urbane and practical personal luxury car. The two-seatThunderbird debuted in 1955, with Ford hoping to sell 10,000 T-birds that first year. Instead they found themselves unable to keep up with consumer demand, with production running into September. Over 16,000 first-year T-birds were sold. Meanwhile, over at GM, less than 5,000 Vettes were sold in its first three years. The Corvette would likely have been discontinued, but the success of the Thunderbird prompted Chevrolet to continue production.

Based on the New Yorker hardtop, the 1955 Chrysler 300 was fitted with heavy-duty suspension, lowered 1.5 inches, and given a 300 horsepower, 331-cid motor hemi-head motor. An optional dual 4-barrel carb setup was available, which produced 355 horsepower. Advertised as "America's Most Powerful Car", the 300 was not successful in sales, but very successful in competition, winning the NASCAR Grand National title, AAA Championship and finishing first-in-class at Daytona's Flying Mile in its first year.

The Studebaker company was in business for over a Century, but are perhaps best known for a model produced only eighteen months. The aerodynamic shape of the fiberglass-bodied Avanti, well-suited for high-speed runs, was the creation of industrial designer Raymond Loewy. Powered by a supercharged 289-cid V-8, a modified Avanti set numerous land speed records at Utah's Bonneville Salt Flats in 1963, including the flying-mile record of 168.15 mph.

On April 1st, 1964, Plymouth introduced the Barracuda, a compact fastback based on the 106-inch wheelbase Valiant model. Sales were lukewarm. Two weeks later, Ford debuted their new compact model, the Mustang. Affordable and stylish, it's good looks and youth-oriented marketing helped make it enormously successful. A GT performance model soon became available, giving the buyer a quick-ratio gearbox, stiffer front coils and rear springs, front disc brakes, and the K-code 271 horsepower 289-cid V-8. More than one-million Mustangs were sold in the first eighteen months of production. Because of its popularity, and the fact that it inspired so many competitors, the Mustang sits in automotive history as the original Pony car.

Although Pontiac wasn't the first car company to drop a big motor in a mid-sized car, they were the first to market a mid-sized car with a big motor. Rivaling anything on the road in straight-line acceleration, the 1964 Tempest-based GTO was wildly successful, prompting others to use the same basic formula. Every U.S. car manufacturer began packaging a factory hot rod with youth-oriented advertising, bringing about the muscle car phenomenon of the Sixties. Designed for straight-line speed, muscle cars lacked sophisticated chassis, brakes, and suspension, but they were durable, affordable, and fast.

The Muscle Car era was short-lived, but gave us some of the most collectible models in classic car history. One of Dodge's best was the 1967 Charger, available with either a 440 Magnum or 426 Hemi, two of the biggest, most powerful motors ever produced. It was the Hemi motor that powered the winged Plymouth Superbirds and Daytona Chargers which dominated the NASCAR racing circuit in 1969 and 1970.

One of the reasons the Chevrolet Camaro did not arrive until 1967 was that many GM executives believed the rear-engine, air-cooled Corvair, popular in the early Sixties, could compete in sales against the Ford Mustang. The Camaro quickly made up for lost time with the potent Z-28 package, and would dominate the SCCA Trans-Am circuit in 1968 and 1969.

Always to have identity issues with its pony car stable-mate the Javelin, the 1968-1970 two-seat AMX was powered by a 390-cid, 315 horsepower V-8, which produced a tire-shredding 415 lb/ft of torque. At 3,000 pounds, the AMX was capable of zero-to-sixty times in under seven seconds, with quarter-mile times under 15 seconds.

European Sports Car History

When Jaguar introduced the XK-120 in 1948, only exotic race machines such as Alfa Romeo, Bugatti and Duesenberg were running double-overhead-cam engines. The twin-cam XK motor was a marvel of engineering, propelling the six-cylinder roadster to 120 miles-per-hour, making it the fastest production car of its day. The same DOHC engine would see another two decades of use, powering the 1961-1970 Jaguar XK-E .

Sports cars like the diminutive Austin-Healey Sprite, the mid-engine Lotus Europa, and the rear-engine Fiat 850 Spider serve as reminders that horsepower is not the only factor to winning races.

The rear-engine, air-cooled Porsche 911 first appeared in 1965. Weighing 2,300 pounds, it displayed brisk handling, great braking, and was capable of speeds over 130 mph. With timeless styling, world-class engineering, and countless race wins, the 911 is considered by many to be the greatest of all classic sports cars.