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.