AMC’s Rebel spent 1967 through 1970 quietly doing everything right, offering full-size room in a midsize body, backing it with the most comprehensive warranty in the industry, and proving the point with a record-setting endurance run down the Baja peninsula. Then in 1970 it produced The Machine, painted red, white and blue, with a 340-horsepower 390 as standard equipment. Read on for how the underdog got loud.