BREAKDOWN

In the summer of 1956 General Motors appointed an engineer named Semon "Bunkie" Knudsen general manager of the company's Pontiac division. Knudsen's marching orders were simple: he had five years to improve the division's sales and if he couldn't do it, GM might shut Pontiac down for good.

In those days Pontiac was America's sixth largest automaker. The cars were affordable and reliable, but they were slow and their styling was outdated; they were the kind of cars that grandparents drove. That was the biggest problem, Knudsen figured. "You can sell a young man's car to an old man," he liked to say, "but you'll never sell an old man's car to a young man."

Knudsen hired E.M. "Pete" Estes, formerly the chief engineer at Oldsmobile, to head the engineering department, and he hired a 31‑year‑old Packard engineer named John Z. DeLorean to be Estes' assistant. Changes came quickly: They immediately began manufacturing high‑performance versions of their existing models. The following year they created the Pontiac Bonneville, a racy fullsized convertible with a big V‑8 engine and fancy bucket seats.

WIDE-TRACKING

For 1959, Knudsen had the designers come up with a new widebodied car with extra-wide tires to boot. These "Wide-Track" Pontiacs had an athletic, broad-shouldered look that caught on quick with younger drivers. By 1960 they were the bestselling midpriced car in the country.

By 1961 Pontiac had done so well that Knudsen was promoted to general manager of Chevrolet. Pete Estes replaced him as the head of Pontiac, and John DeLorean became the chief engineer. Together, they were about to come up with the most famous Pontiac ever.

OUT OF THE RACE

From 1959 to 1963, Pontiac had dominated the NASCAR circuit with their custom‑built race cars, but then GM decided to stop producing them so they could focus on selling higher‑profit consumer vehicles. All auto divisions were banned from any participation in motorsports. The divisions weren't even allowed to assist professional race car drivers. Estes was miffed about the restriction‑he didn't want to lose the association with sports. So he decided that if he couldn't put a race car on a race track, he'd start putting them on the street.

He and DeLorean used the same trick that hot‑rodders had used for years: They took the giant engine out of the full‑sized Pontiac Bonneville and dropped it into the mid‑sized Pontiac Tempest LeMans. They added lots of other goodies, too: high performance carburetors, a heavy duty clutch and suspension, dual chrome exhausts, an air scoop on the front hood, and an optional 4‑speed manual transmission with a stick shift on the floor.

SECRET WEAPON

It's not uncommon for auto companies to hide new models from the public, but Estes and DeLorean hid it from their bosses at GM. Putting such a huge engine into a car that small was against company rules, so rather than introduce the car as a new model, they called it an "option package" for the Pontiac LeMans instead, hoping that nobody would realize what they were up to.

DeLorean named the souped up LeMans the GTO, which was short for Gran Turisimo Omologato. Omologato is the Italian word for homologous, which means "all coming from the same thing." Whereas most custom‑built hot rods of the time were pieced together from different cars and "aftermarket" parts, the GTO was truly homologous‑all of its parts came from Pontiac. This made it America's first "factory hot rod," or "muscle car."

Calling the GTO an option package for the LeMans paid off: by the time the bosses at GM realized what was happening, car dealers had already placed orders for 5,000 of the cars, so GM grudgingly agreed to let the car be built. Whatever anger the company had toward Estes and DeLorean disappeared when more than 32,000 GTOs sold that first model year alone, and 75,000 in 1965. The car was a smash hit, and GM not only allowed the GTO to become a model in its own right for 1966 (it sold nearly 97,000 cars that year), it also made plans for its other divisions to produce their own muscle cars, including the Chevy Chevelle SS, the Buick Regal Gran Sport, and the Oldsmobile Cutlass 442.

MUSCLE CARS EVERYWHERE

Over the next few years the Big Three automakers got into the act, too: Ford introduced the Fairlane GT, the Mercury Cyclone GT, and the Ford Torino Cobra. Chrysler came out with the Dodge Charger and the Plymouth Road Runner, to name just a few. Each year the engines got bigger and more powerful. The 1964 Pontiac GTO had a 325 horsepower engine; by 1971 the Plymouth Road Runner had a 425 horsepower engine.

END OF THE ROAD

Muscle cars were popular because they were cheap and fast-a brand-new 1964 GTO convertible cost only $3,081-and though many got less than 10 miles to the gallon, gas only cost about 25 a gallon so it wasn't a problem. Muscle cars took to the road by the tens of thousands in the late 1960s and early 1970s.

And then by 1973 they were gone.

What happened? For one thing, when the auto insurance industry realized that muscle cars were little more than street‑legal race cars, they raised their rates so high that many people paid more for insurance than they did for their monthly car payment. Then in 1973 the Arab oil embargo caused the price of gasoline to soar. Suddenly cheap muscle cars weren't so cheap anymore. To make things worse, they were also coming under increased criticism from environmentalists and car safety advocates.

The automakers were also being pressured by the federal government to build more fuel‑efficient cars that could run on regular or unleaded gas. In 1974 Pontiac came out with a muscle car without any muscle, a GTO with only 200 horsepower. In 1975 they didn't even bother. The GTO bit the dust, just like nearly every other muscle car it inspired.

If you missed your chance to own a GTO, cheer up. Pontiac brought a new one to market in 2004. Price: $32,495, quite a lot more than a new GTO cost forty years ago, but about as much as you can expect a classic GTO in excellent condition to cost you today.