In the 1960s, American muscle cars were built for straight-line violence. Big V8s, two-door coupes, and quarter-mile bragging rights were the order of the day. Yet one machine refused to follow the usual script. The 1965 Shelby 427 Cobra took the delicate shape of a British roadster and dropped in Ford's thundering 427 FE big-block V8. It was an odd marriage, but it worked like a charm. The...