The DeSoto Firesweep, particularly the 4-Door Sedan facelifted for 1958 with the 5.7L V8 and PowerFlite automatic transmission, represents a pivotal, though ultimately short-lived, moment in the American automotive landscape. Produced from 1957 to 1958, this variant occupied a middle ground within the Firesweep lineup, offering a balance of power and convenience aimed at the family sedan market. It was built upon the corporate platform shared with Dodge and Plymouth, reflecting Chrysler Corporation’s strategy of maximizing efficiency and component sharing. The 1958 facelift brought significant styling changes, attempting to capture the burgeoning tastes for more extravagant designs, but it wasn’t enough to save the DeSoto brand from eventual discontinuation.
Technical Specifications
| Brand | DeSoto |
| Model | Firesweep |
| Generation | Firesweep I 4-Door Sedan (facelift 1958) |
| Type (Engine) | 5.7 V8 (280 Hp) PowerFlite |
| 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 | 280 Hp @ 4600 rpm |
| Power per litre | 48.8 Hp/l |
| Torque | 515 Nm @ 2400 rpm / 379.84 lb.-ft. @ 2400 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 | 76 l / 20.08 US gal | 16.72 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 (Back) 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 (turning diameter) | 14.2 m / 46.59 ft. |
| Approach angle | 16.5° |
| Departure angle | 11.4° |
| Ramp-over (brakeover) angle | 10.5° |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 2 gears, automatic transmission PowerFlite |
| 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 the 1958 Firesweep was the Chrysler-built 5.7-liter (349.97 cubic inch) V8 engine. This engine, designated with various codes depending on specific calibration, produced 280 horsepower at 4600 rpm and 515 Nm (379.84 lb-ft) of torque at 2400 rpm. It featured a cast iron block and cylinder heads, with a 10:1 compression ratio. The engine utilized a single carburetor for fuel delivery and an overhead valve (OHV) valvetrain. The PowerFlite automatic transmission, a two-speed unit, was the standard transmission offering for this variant. The PowerFlite, while providing ease of use, was a relatively simple design compared to some of its competitors, prioritizing durability over outright performance. It was a torque converter automatic, offering smooth, but not particularly quick, shifts.
Driving Characteristics
The combination of the 280 hp V8 and the two-speed PowerFlite transmission resulted in a driving experience geared towards comfortable cruising rather than spirited acceleration. While the engine provided ample torque for everyday driving and highway passing, the limited number of gears in the PowerFlite meant that the engine often operated at higher RPMs, impacting fuel economy. Compared to the available manual transmission options or the higher-output V8s found in other Chrysler models, the Firesweep 1.8L Automatic felt less responsive. The gear ratios were optimized for relaxed driving, making it a suitable choice for families prioritizing comfort over performance.
Equipment & Trim Levels
The 1958 Firesweep 4-Door Sedan with the 5.7L V8 and PowerFlite typically came standard with features considered essential for the time, including a spacious interior with seating for six, full wheel covers, a heater, and a basic AM radio. Upholstery was typically cloth and vinyl, with a focus on durability. Optional extras included power steering, power brakes, a continental kit, and upgraded trim packages. The Firesweep occupied a mid-range position within the DeSoto lineup, offering more features than the base models but lacking the luxury appointments of the higher-end Adventurer trim.
Chassis & Braking
The Firesweep utilized a body-on-frame construction, common for American cars of the era. The front suspension was independent, employing coil springs, while the rear suspension relied on a traditional leaf spring setup. Braking was accomplished via drum brakes on all four wheels, measuring 279mm in diameter. Steering was handled by a worm-reduction unit, providing relatively heavy but direct steering feel. The chassis was designed for comfortable ride quality, prioritizing smoothness over sharp handling.
Market Reception & Comparison
The 1958 DeSoto Firesweep faced stiff competition from other American manufacturers, including Ford, Chevrolet, and Plymouth. Critics generally praised the Firesweep’s styling and comfortable ride, but noted that its performance was not class-leading. The PowerFlite transmission, while convenient, was often criticized for its limited gear range and impact on fuel economy. Compared to the more performance-oriented versions of the Firesweep, such as those equipped with higher-output V8s and manual transmissions, the 5.7L Automatic variant appealed to a different demographic – those seeking a comfortable and reliable family sedan.
Legacy
The DeSoto Firesweep, and the DeSoto brand as a whole, was discontinued after 1961 due to declining sales and increasing competition. However, the 1958 Firesweep, particularly the 5.7L V8/PowerFlite combination, has gained a following among classic car enthusiasts. The engine, while not particularly sophisticated by modern standards, is known for its durability and relative ease of maintenance. Parts availability can be a challenge, but a dedicated community of DeSoto owners and restorers helps to keep these vehicles on the road. Today, the 1958 Firesweep represents a unique and stylish piece of American automotive history, offering a glimpse into a bygone era of large, comfortable, and relatively affordable automobiles.
