AS GENERAL MOTORS BEGAN TO realize in the early 1960s, bigger was not always better. In 1955, Chevrolet’s One-Fifty, Two-Ten, and Bel Air models all rode on a 115-inch wheelbase, with coupes and sedans measuring 195.6 inches from bumper to bumper. By 1961, Chevrolet’s Biscayne, Bel Air, and Impala had grown to 209.3 inches in length, riding on a longer 119-inch wheelbase. Sales, however, had not kept pace: In 1955, Chevrolet sold 1.7 million cars (excluding Corvette), but by 1961, full-size production failed to reach 1.2 million units, and that was just one GM division.
Enter the 1964 GM A-body platform, which underpinned a range of intermediate-sized models from Chevrolet, Buick, Oldsmobile, and Pontiac. With a return to a 115-inch wheelbase (excluding station wagons, which rode a stretched 120-inch wheelbase),…