The 1960s muscle car script was wonderfully simple: take a sensible midsize coupe, stuff the largest V8 the factory could wedge between the fenders, and sell it to anyone with a steady job and a pulse. Mustangs, Chevelles, and Barracudas flew off lots like hotcakes, thanks to price tags that hovered around the low-to-mid two-thousand-dollar mark. Insurance was cheap, gasoline even cheaper, and...