Shelby GT 500KR (1964-1968)
The "KR" is for "King of the Road," and that's what the Shelby is. What ran you $64,000 in 2001 has jumped to $100,000, or as high as $5.5 million for some special orders [source: CNNMoney.com]. The Original GT 500KR advertised a V-8 with 360 horses, making it the only non-American muscle car worth talking about among collectors. Its popularity and rarity remained constant throughout the four years of its major sale, and it has remained in these lists -- and discussed among fans in hushed tones -- ever since.
The 1964 Cobra 289 roadster ($175,000 in 2000, now $330,000 to $5.5 million for the one-of-a-kind "Super Snake") is much beloved among the highest echelons of muscle car fanatics [source: CNNMoney.com]. The 1966 Shelby Cobra 427 S/C had too much power for its chassis, albeit along with an impressive 480 horsepower. In fact, a special order for Bill Cosby, turbocharged, ended up in a lake after he sold it for being too powerful. The only other version of this ultra-elite muscle remains with Shelby, a cautionary tale about the limits of muscle … or perhaps an inspiration.