That was certainly the case with one of ex-racer Carroll Shelby's most famous cars. For 1965, he began production of hopped-up Mustangs at his shop in California. For those first couple years, his 'Stangs, called GT-350s, were barely-disguised competition tools.

With a road-racing suspension setup, high-strung small-block V8, and lack of a backseat on which to haul buddies, those original GT-350s weren't a popular pick with the burger-joint crowd. And that was fine with Ford, at least at first -- Shelby's cooperation on the Mustang was initially sought to give competition credibility to Ford's pioneering ponycar, which GT-350s did handily by winning sports-car races.

But starting with the '67 model year, Ford began expecting Shelby's machines to speak to a more mainstream performance crowd -- the typical muscle-car buyer.

Signaling this shift toward street appeal over race-track prowess were mandatory power steering and power brakes, along with a number of optional comfort and convenience features, including air conditioning, tilt steering wheel, and tinted glass.

And, perhaps most importantly, a backseat was now standard.

But despite the added weight of such amenities, Shelby's machines hadn't lost their bite. Although the base GT-350's V8 was now somewhat tamer, that model for '67 was joined by the new GT- 500, powered by a torquey 428-cid big-block V8 rated at 360 hp.

For '68, the GT-500 packed an even bigger wallop, with the midyear introduction of the GT-500KR "King of the Road," which had a 428 that was some 40 hp stouter yet. Also that year, the Shelby Mustang's fastback bodystyle was joined by a convertible, to further appeal to the boulevard cruising set.

Development and production of Shelbys continued along similar lines into the next generation of Mustangs, ending in 1970.

Today, muscle-car fans are divided on which of the Shelby Mustangs are the greatest -- the almost race-ready early versions, or the punchier, plusher, more street-appropriate later ones. Regardless, any flavor of Shelby Mustang is counted among the great performance cars, a fact clearly reflected in the hefty prices these cars command nowadays.

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About the Author

David Bellm is a seasoned test driver and automotive historian. His work has been featured in a wide variety of online and print publications.

A Quick Note From The Publisher... If you like the article above, you may be interested in the following article which is also related to Mustangs... The Story Of The Ford Mustang The Ford Mustang is one of the best known and easily recognized vehicles on the road today. Who doesn't recognize the sporty chrome pony emblazoned on the shiny paint of a Ford Mustang? But I bet many of you don't know the history of the Mustang. Well jump in your time capsule and join me for a ride back to the year 1964. To be more specific, March 9, 1964. That was the day that the first Ford Mustang rolled off the assembly line – it was a white convertible with a red interior. It created a sensation all across the nation. As a matter of fact, within 18 months, Ford sold over 1 million Mustangs! Just months after its introduction, Ford began introducing changes for the '65 Mustang, including a bigger engine, reverse lights, and an AC alternator. In the first two years of its existence, the Mustang broke sales records, wowed the public, and left competitors in the dust. The next job for the Mustang was to take down the Chevrolet Corvette in the world of racing. That job was...

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