Perhaps one of the greatest American cars of all time.
Ford wasted very little attaching Carroll Shelby to the Mustang project. By the time the first Mustang rolled off the assembly line, Ford had already worked with Shelby on his Cobra cars, as well as their own GT40. These were high-dollar exotics, blindingly fast but also priced well out of reach of most customers. The Shelby Mustangs made Shelby-branded performance available to the middle classes. These weren't exactly cheap themselves, but they were (and now are again) excellent value for a performance car.
The Ford Mustang was introduced in 1964, or "1964 1/2 ", as Ford likes to say, and was the brainchild of Lee Iacocca. Iacocca had watched the racing success of the Cobra, and its "Powered by Ford" badges, and recognized the potential to expand the Cobra/Shelby name. He approached Shelby with the idea of a Mustang which both evoked elements of the Cobra and would also be fast enough to beat a Corvette on the track. The result was the Shelby GT350, which would later come to be known as the Shelby Cobra 350, and then would drop the Cobra name again.
The 1965 and '66 models of the GT350 are considered the most pure examples, as the Mustang would get bigger and heavier by 1967. These early GT350 models were, like the Cobra, extremely focused on performance, and there was little in the creature comforts or anything else which didn't make the car go faster. The painted stripes and valve covers with "Cobra" stamped on them were meant to evoke the Cobra, but the engine is the bigger similarity. This was the Ford 289 V8, an engine which was also available in the regular Mustang, but was here tuned to produce 306 horsepower, just as it was in the Mark II Cobra.
The 1965 model was available only in Wimbledon White with Guardsman Blue stripes, and only with a 4-speed manual transmission. Fewer than 30 GT350R racings versions of the car were built, but Iacocca got his wish that they would beat the Corvette on the track when they took the SCCA B-Production class championship in '65, '66 and '67. Even rarer, some 1966 models were equipped with Paxton superchargers, a modification which allowed them to produce 440 horsepower. With the heavier 1967 stock Mustang, a more powerful Shelby Mustang was introduced for sale alongside the GT350.
Although Carroll Shelby would be less and less involved with the project by the end of 1967, it is this more powerful Mustang which most people think of in connection to Shelby Mustangs. This Mustang was the GT500, and the 1967 GT500 used for the remake of "Gone in 60 Seconds", going by the name "Eleanor", is the most instantly recognizable of Shelby Mustangs. The engine for the GT500 was the 428 Cobra Jet, one adapted from Ford's Police Interceptor power plant. This engine was underrated by Ford in an attempt to curb the high insurance costs which by 1967 were hurting muscle car sales.
So although Ford literature rates the engine at 335 horsepower, the actual figure is somewhere closer to 410 horsepower. The Cobra Jet is also a very tough engine, with a strengthened bottom end which makes it more easily modified for use with a supercharger or nitrous oxide. By 1969, Carroll Shelby was no longer really involved with the Mustangs which bore his name, and they had been reduced to what basically amounted to appearance packages for the Mustang. Not surprisingly, the Shelby Mustangs were discontinued in 1970. The name Cobra would be revived in the Nineties by Ford's Special Vehicle Team.
However, it wasn't until 2006 when the actual Shelby name would be once again attached to a Mustang. This Mustang was the Shelby GT-H, a mild tuning job intended to mark the 40th anniversary of the GT350H, an edition of the original car which was built for the Hertz rental car agency. This was fine, but it was in 2007, with the reintroduction of the GT500 nameplate, that the Shelby Mustang was really reborn. This new GT500 produced 500 horsepower from a supercharged 5.4-liter V8, and power would climb to 550 horsepower before Ford decided to replace the engine.
The 2013 GT500 now produces 662 horsepower, and is a fitting tribute to the original if ever there was one. The official top speed is 202mph, but a few months ago I spoke to an SVT engineer (who wishes to remain anonymous) and he showed me a video on his phone of the test mule on the track at the Nardo Ring doing 207mph. Just so you know. A few variations of the of GT500 exists as well, including the 862-horsepower Super Snake and the recently revealed Shelby 1000, which produces either 920 horsepower or 1100 horsepower, depending on whether it's in street or race trim.
Without question, the Shelby Mustangs are some of the finest examples of the breed, and both the Mustang and Carroll Shelby came away as bigger hits as a result of the relationship.