During the fabulous 1960s, American engineers lived by the creed, "There's no replacement for displacement." The myriad of high-performance muscle car big-block V8s developed during that decade were a statement of that belief. Still, unquestionably, the best example was the gargantuan Twin Six, ...

Without the use of turbos, superchargers, or any electric motors, these five supercars have pushed the boundaries of naturally aspirated internal combustion engines to a different level of performance. When turbos became the norm in the automotive industry during the 1960s and 1970s, many ...