As if the production Mustang wasn't hot enough, legendary Texas tuner Carroll Shelby collaborated with Ford in 1965 on these special GT350 models. These were basically street-legal versions of Shelby's GT350R race car, powered by Ford's 289 Hi-Po small-block. The legend grew the following year when rental company Hertz snapped up some Shelbys as part of their "Rent-a-Racer" program. Some were apparently returned with their high-power engines myseriously swapped out. Huh.