The DeSoto Firesweep I 4-Door Sportsman, as presented in its 1958 facelift, represented a significant offering from the Chrysler Corporation’s mid-range brand. Produced for the 1957 and 1958 model years, the Firesweep occupied a space between the more affordable Plymouth and the luxury-oriented Chrysler models. This particular variant, equipped with the PowerPack 5.7 V8 engine paired with a TorqueFlite automatic transmission, was positioned as a comfortable and powerful family sedan, aimed at buyers seeking a blend of style, performance, and convenience. The Firesweep was built on the Chrysler A-body platform, shared with other models like the Dodge Coronet, and was a key part of DeSoto’s attempt to establish a distinct identity in the American automotive market.
Technical Specifications
| Brand | DeSoto |
| Model | Firesweep |
| Generation | Firesweep I 4-Door Sportsman (facelift 1958) |
| Type (Engine) | PowerPack 5.7 V8 (295 Hp) TorqueFlite |
| Start of production | 1957 |
| End of production | 1958 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 6 |
| Doors | 4 |
| Fuel Type | Petrol (Gasoline) |
| Power | 295 Hp @ 4600 rpm |
| Power per litre | 51.4 Hp/l |
| Torque | 522 Nm @ 2800 rpm / 385.01 lb.-ft. @ 2800 rpm |
| Engine displacement | 5735 cm3 / 349.97 cu. in. |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 103.12 mm / 4.06 in. |
| Piston Stroke | 85.85 mm / 3.38 in. |
| Compression ratio | 10:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Carburettor |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV |
| Engine oil capacity | 3.8 l / 4.02 US qt | 3.34 UK qt |
| Coolant | 16.1 l / 17.01 US qt | 14.17 UK qt |
| Fuel tank capacity | 87 l / 22.98 US gal | 19.14 UK gal |
| Length | 5499 mm / 216.5 in. |
| Width | 1989 mm / 78.31 in. |
| Height | 1443 mm / 56.81 in. |
| Wheelbase | 3099 mm / 122.01 in. |
| Front track | 1547 mm / 60.91 in. |
| Rear track | 1516 mm / 59.69 in. |
| Front overhang | 940 mm / 37.01 in. |
| Rear overhang | 1461 mm / 57.52 in. |
| Ride height (ground clearance) | 142 mm / 5.59 in. |
| Minimum turning circle | 14.2 m / 46.59 ft. |
| Approach angle | 16.5° |
| Departure angle | 11.4° |
| Ramp-over angle | 10.5° |
| Drivetrain Architecture | Rear wheel drive. Internal Combustion engine (ICE) |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 3 gears, automatic transmission TorqueFlite |
| Front suspension | Independent coil spring |
| Rear suspension | Leaf spring |
| Front brakes | Drum, 279 mm |
| Rear brakes | Drum, 279 mm |
| Steering type | Worm-reduction unit |
Powertrain & Engine Architecture
The heart of this Firesweep variant was the DeSoto PowerPack 5.7 V8 engine. This engine, displacing 349.97 cubic inches (5735 cm3), 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 PowerPack designation indicated a slightly higher performance version of the standard DeSoto V8, achieved through improved cylinder head flow and a more aggressive camshaft profile. The engine produced 295 horsepower at 4600 rpm and 385 lb-ft of torque at 2800 rpm, making it a potent powerplant for the era. The TorqueFlite automatic transmission, a three-speed unit, was Chrysler Corporation’s answer to the Hydra-Matic. It was known for its smoothness and durability, and was a popular option for DeSoto buyers who preferred the convenience of an automatic over a manual transmission.
Driving Characteristics
The combination of the 5.7 V8 and the TorqueFlite automatic transmission resulted in a driving experience that prioritized smooth acceleration and relaxed cruising. While not a sports car, the Firesweep offered ample power for highway passing and merging. The TorqueFlite’s gear ratios were optimized for comfortable driving, with a focus on providing strong low-end torque. Compared to the manual transmission versions, the automatic offered less driver involvement but greater ease of use, particularly in city traffic. The 1958 Firesweep, being a full-size American sedan, was not known for nimble handling. The suspension, while comfortable, was tuned for a soft ride rather than sporty cornering. The rear leaf spring suspension contributed to a somewhat floaty feel, especially on uneven roads.
Equipment & Trim Levels
The 1958 Firesweep 4-Door Sportsman with the PowerPack V8 and TorqueFlite transmission was a well-equipped vehicle for its time. Standard features typically included a spacious interior with comfortable bench seats upholstered in durable cloth or vinyl. The dashboard featured a combination of analog gauges, including a speedometer, fuel gauge, and temperature gauge. Power steering and power brakes were often included as standard equipment, enhancing the driving experience. Optional extras included air conditioning, a radio, and whitewall tires. The interior trim levels varied, with higher-end models offering more luxurious upholstery and additional chrome accents.
Chassis & Braking
The Firesweep utilized a body-on-frame construction, typical of American cars of the 1950s. The chassis featured an independent coil spring suspension in the front, providing a relatively comfortable ride. The rear suspension employed a traditional leaf spring setup. Braking duties were handled by drum brakes on all four wheels, measuring 279mm in diameter. While adequate for the car’s weight and performance, the drum brakes lacked the stopping power of modern disc brakes. Steering was accomplished through a worm-reduction unit, which provided relatively heavy but precise steering feel.
Market Reception & Comparison
The 1958 DeSoto Firesweep was generally well-received by automotive critics, who praised its stylish design, comfortable ride, and powerful engine. However, it faced stiff competition from other mid-range American cars, such as the Ford Fairlane and the Chevrolet Bel Air. The Firesweep’s fuel economy, typical of large V8-powered cars of the era, was relatively poor. Reliability was generally good, but the carburetor could require occasional adjustments. Compared to the base Firesweep models with smaller engines, the PowerPack V8 version offered a significant performance upgrade, but at a higher price point. Compared to the higher-trim DeSoto Adventurer, the Firesweep offered a more affordable entry point into the DeSoto lineup, sacrificing some of the Adventurer’s luxury features and performance.
Legacy
The DeSoto Firesweep, and the DeSoto brand as a whole, ultimately faded into automotive history. Production ceased in 1961 due to declining sales and Chrysler’s decision to streamline its model offerings. However, the Firesweep remains a popular choice among classic car enthusiasts. The PowerPack 5.7 V8 engine is known for its durability and relative ease of maintenance, making it a reliable powerplant for restoration projects. Today, well-maintained 1958 Firesweep models are sought after by collectors and represent a nostalgic reminder of the American automotive landscape of the late 1950s. The TorqueFlite transmission, if properly maintained, continues to provide smooth and reliable operation even after decades of use.
