1958-1959 DeSoto Firesweep I Convertible (facelift ) 5.9 V8 (295 Hp) TorqueFlite

The DeSoto Firesweep I Convertible, particularly the 1959 facelifted model, represents a pivotal moment in the twilight of the DeSoto marque. Produced for a brief period between 1958 and 1959, it was positioned as a full-size luxury convertible, embodying the flamboyant styling of the late 1950s American automotive industry. This variant, equipped with the 5.9-liter V8 engine producing 295 horsepower and paired with a TorqueFlite automatic transmission, aimed to deliver a blend of performance and convenience to the discerning American buyer. The Firesweep occupied a middle ground within the DeSoto lineup, offering a more accessible entry point into the brand’s luxury offerings compared to the flagship Firesweep Sportsman.

Technical Specifications

Powertrain & Engine Architecture

The heart of the 1959 Firesweep Convertible was the DeSoto 5.9-liter (361 cubic inch) V8 engine. This engine, designated within the Chrysler corporation as the “RB” series, was a robust and relatively modern design for its time. It featured a cast iron block and cylinder heads, with a 10:1 compression ratio. The engine utilized a single Carter carburetor, providing fuel delivery to the overhead valve (OHV) configuration with two valves per cylinder. The 295 horsepower output was achieved at 4600 rpm, while peak torque of 529 Nm (390.17 lb-ft) arrived at a relatively low 2400 rpm, providing ample low-end grunt for comfortable cruising. The TorqueFlite automatic transmission, a three-speed unit, was standard. This transmission was known for its smoothness and durability, contributing to the Firesweep’s reputation as a refined cruiser.

Driving Characteristics

The combination of the 5.9-liter V8 and the TorqueFlite automatic transmission resulted in a driving experience geared towards comfortable, effortless touring. While not a performance-oriented machine, the Firesweep offered brisk acceleration, particularly considering its substantial weight. The TorqueFlite’s gear ratios were optimized for smooth shifts and relaxed highway cruising. Compared to a manual transmission-equipped Firesweep, the automatic version sacrificed some responsiveness, but gained significantly in ease of use. The relatively low gearing also meant that fuel economy, even by 1959 standards, was not a strong suit. The suspension, featuring independent torsion bars up front and leaf springs in the rear, provided a reasonably comfortable ride, though it wasn’t particularly sporty or precise.

Equipment & Trim Levels

The 1959 Firesweep Convertible, even in its base form, was well-equipped for the era. Standard features included full wheel covers, whitewall tires, a heater, and a deluxe steering wheel. The interior typically featured cloth and vinyl upholstery, with a focus on spaciousness and comfort. Optional extras included power steering, power brakes, a radio, and a continental kit. The Firesweep Convertible offered a more luxurious interior trim than the base Firesweep models, with more extensive use of chrome and brightwork. The dashboard layout was typical of the late 1950s, featuring a large speedometer and fuel gauge, along with smaller indicators for temperature and oil pressure.

Chassis & Braking

The Firesweep Convertible rode on a traditional body-on-frame chassis. The front suspension utilized independent torsion bars and a double wishbone setup, while the rear employed leaf springs. This configuration provided a reasonable balance of ride comfort and handling, although it wasn’t particularly sophisticated by modern standards. Braking was accomplished via drum brakes on all four wheels, measuring 279mm in diameter. While adequate for the time, the drum brakes lacked the stopping power and fade resistance of disc brakes. Power steering and power brakes were available as optional extras, enhancing the driving experience.

Market Reception & Comparison

The 1959 Firesweep Convertible received generally positive reviews from automotive journalists of the time. It was praised for its stylish design, comfortable ride, and powerful V8 engine. However, critics also noted its substantial size and weight, as well as its relatively high price. Compared to other full-size convertibles of the era, such as the Ford Fairlane 500 Skyliner and the Chevrolet Bel Air, the Firesweep offered a more luxurious and refined experience, but at a higher cost. Fuel economy was also a concern, as with most large American cars of the late 1950s. The Firesweep’s reliability was generally considered to be good, although maintenance costs could be significant due to the complexity of the V8 engine and automatic transmission.

Legacy

The DeSoto Firesweep Convertible, and the Firesweep line in general, represents a poignant chapter in American automotive history. Production ceased in 1961, marking the end of the DeSoto brand. Today, the 1959 Firesweep Convertible is a sought-after classic car, prized for its distinctive styling and nostalgic appeal. The 5.9-liter V8 engine, while not known for exceptional fuel efficiency, is generally considered to be a durable and reliable powerplant. Parts availability can be a challenge, but a dedicated community of DeSoto enthusiasts ensures that restoration and maintenance are still possible. The TorqueFlite transmission, if properly maintained, continues to provide smooth and reliable performance. The 1959 Firesweep Convertible stands as a testament to the optimism and extravagance of the late 1950s American automotive era.