The DeSoto Firesweep, particularly the 1958 facelifted 4-door sedan equipped with the PowerPack 5.7 V8 and TorqueFlite automatic transmission, represents a pivotal, though ultimately short-lived, moment in the American automotive landscape. Produced from 1957 to 1958, the Firesweep occupied a middle ground within the DeSoto lineup, positioned above the entry-level Fireside but below the more luxurious DeSoto Adventurer. This variant aimed to offer a blend of performance and comfort, appealing to buyers seeking a stylish and powerful family sedan. The 1958 model year saw a significant restyling, with a more pronounced tailfin design and revised trim, reflecting the era’s fascination with futuristic aesthetics.
Technical Specifications
| Brand | DeSoto |
| Model | Firesweep |
| Generation | Firesweep I 4-Door Sedan (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 |
| Torque (lb-ft) | 385.01 lb.-ft. @ 2800 rpm |
| Engine displacement | 5735 cm3 |
| Engine displacement (cu. in.) | 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 capacity | 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 |
| Drive wheel | Rear wheel drive |
| Number of gears | 3 |
| Gearbox type | 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 the 1958 Firesweep was the DeSoto PowerPack 5.7-liter (349.97 cubic inch) V8 engine. This engine, designated with various codes depending on specific configurations, was a robust and relatively advanced design for its time. It featured a cast iron block and aluminum cylinder heads, utilizing a conventional overhead valve (OHV) valvetrain with two valves per cylinder. Fuel delivery was managed by a Carter carburetor, a common setup for American V8s of the era. The 10:1 compression ratio contributed to the engine’s respectable 295 horsepower at 4600 rpm and 385 lb-ft of torque at 2800 rpm. The TorqueFlite automatic transmission, a three-speed unit, was the sole transmission option for this variant. It was known for its smoothness and durability, though it lacked the efficiency of more modern automatics.
Driving Characteristics
The combination of the 5.7L V8 and the TorqueFlite transmission provided a comfortable and capable driving experience. While not a sports car, the Firesweep offered brisk acceleration for its size and weight. The TorqueFlite’s gear ratios were optimized for cruising, making it well-suited for highway driving. Compared to the manual transmission options available on other DeSoto models, the automatic version prioritized ease of use over outright performance. The automatic transmission did slightly diminish the engine’s potential, but it appealed to a broader audience seeking a more relaxed driving experience. The leaf spring rear suspension provided a comfortable ride, but it wasn’t particularly sporty in handling.
Equipment & Trim Levels
The 1958 Firesweep 4-door sedan with the PowerPack V8 and TorqueFlite typically came standard with features considered luxurious for the time. These included full wheel covers, a two-tone paint scheme, and a spacious interior upholstered in cloth and vinyl. Power steering and power brakes were often included, though air conditioning was typically an optional extra. The dashboard featured a prominent instrument cluster with gauges for speed, fuel, temperature, and oil pressure. Interior trim options varied, with higher-grade materials and more elaborate designs available as upgrades.
Chassis & Braking
The Firesweep rode on a conventional body-on-frame chassis. The front suspension utilized independent coil springs, providing a relatively comfortable ride. The rear suspension employed leaf springs, a common design for American cars of the period. 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. Steering was handled by a worm-reduction unit, which provided a relatively heavy but precise feel.
Market Reception & Comparison
The 1958 Firesweep, while well-regarded for its styling and power, faced stiff competition from other American manufacturers. Critics generally praised the V8 engine’s performance and the TorqueFlite transmission’s smoothness. However, some noted the car’s relatively high price compared to competitors like Ford and Chevrolet. Fuel economy, typical for a large American car of the era, was not a strong point. Compared to the more performance-oriented DeSoto Adventurer, the Firesweep offered a more balanced blend of comfort and power. The Fireside, the entry-level model, provided a more affordable option but lacked the V8’s punch.
Legacy
The DeSoto Firesweep, and the DeSoto brand as a whole, was discontinued after the 1961 model year. The 1958 Firesweep with the PowerPack V8 and TorqueFlite remains a collectible classic, particularly among enthusiasts of 1950s American automobiles. The PowerPack V8 engine, while not known for exceptional longevity, is generally considered reliable when properly maintained. Parts availability can be a challenge, but a dedicated network of suppliers caters to the classic DeSoto community. Today, these cars represent a unique chapter in American automotive history, embodying the optimism and design flair of the late 1950s.
