Although the Thunderbird had been considered a rousing success, Ford executives—particularly Robert McNamara – felt that the car’s position as a two-seater restricted its sales potential.
As a result, the car was redesigned as a four-seater for 1958. Though retaining a design as a two-door hardtop coupe/convertible, the new Thunderbird was considerably larger than the previous generation, with a longer 113.0 inches (2,870 mm) wheelbase to accommodate the new back seat. The increased size also increased the car’s weight significantly by close to 1,000 pounds (454 kg).
Along with a new, more rigid unibody construction was new styling, including dual headlights , more prominent tailfins, a bolder chrome grille, and a larger, though non-functional, hood scoop. Powering the Thunderbird was a new, 300 horsepower (220 kW) 352 cu in (5.8 L) FE V8, available with a 3-speed manual or automatic transmissions. With 37,892 sold in 1958—outselling the previous model year by well over 16,000 units—the new Thunderbird began a sales momentum previously unseen with the car.
It was also history-making, becoming the first individual model line (as opposed to an entire company) to earn Motor Trend “Car of the Year” honors. With little more than a new grille and a newly optional, 350 horsepower (260 kW) 430 cu in (7.0 L) MEL V8 for 1959, sales climbed even higher to 67,456. For 1960, the Thunderbird was given another new grille and other minor stylistic changes along with a newly optional manually operated sunroof for hardtop models. Dual-unit round taillights from 1958 to 1959 were changed to triple-units after the fashion of the Chevrolet Impala. Customers continued to approve of the car as it broke sales records yet again with 92,843 sold for 1960. In spite of this success, Ford went ahead with a redesign for the Thunderbird to debut in 1961.