The DeSoto Firedome III Four-Door Sportsman, specifically the 1958 facelift model, represented a pinnacle of American automotive styling and engineering during the late 1950s. Produced for the 1957 and 1958 model years, it was positioned as a premium offering within the DeSoto lineup, slotting above the Firesweep and alongside the Adventurer. This particular 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 luxury, performance, and comfortable cruising for American families. The Firedome III was a key model for DeSoto, embodying the brand’s focus on bold design and powerful engines during a period of intense competition in the American automotive market.
Technical Specifications
| Brand | DeSoto |
| Model | Firedome |
| Generation | Firedome III Four-Door Sportsman (facelift 1958) |
| Type (Engine) | 5.9 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 | 49.9 Hp/l |
| Torque | 529 Nm @ 2400 rpm / 390.17 lb.-ft. @ 2400 rpm |
| Engine displacement | 5916 cm3 / 361.02 cu. in. |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 104.65 mm / 4.12 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 | 5552 mm / 218.58 in. |
| Width | 1989 mm / 78.31 in. |
| Height | 1450 mm / 57.09 in. |
| Wheelbase | 3200 mm / 125.98 in. |
| Front track | 1549 mm / 60.98 in. |
| Rear track | 1516 mm / 59.69 in. |
| Front overhang | 892 mm / 35.12 in. |
| Rear overhang | 1461 mm / 57.52 in. |
| Ride height (ground clearance) | 140 mm / 5.51 in. |
| Minimum turning circle | 15.1 m / 49.54 ft. |
| Approach angle | 16.3° |
| Departure angle | 11.6° |
| Ramp-over angle | 10° |
| Drivetrain Architecture | Rear wheel drive |
| 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, 305 mm |
| Rear brakes | Drum, 305 mm |
| Steering type | Worm-reduction unit |
Powertrain & Engine Architecture
The heart of the 1958 DeSoto Firedome III was the 5.9-liter (361 cubic inch) V8 engine. This engine, designated within Chrysler’s engine family as the “RB” series, featured a cast iron block and aluminum cylinder heads. It utilized a conventional overhead valve (OHV) configuration with two valves per cylinder. Fuel delivery was managed by a Carter carburetor, a common setup for the era. The 10:1 compression ratio contributed to the engine’s respectable 295 horsepower output at 4600 rpm and 529 Nm (390 lb-ft) of torque at 2400 rpm. The TorqueFlite automatic transmission, a three-speed unit, was the sole transmission option for this model. This transmission was known for its smoothness and durability, and it was a key selling point for DeSoto buyers seeking a comfortable driving experience.
Driving Characteristics
The combination of the 295 hp V8 and the TorqueFlite automatic transmission provided a smooth and powerful driving experience. While not a sports car, the Firedome III offered brisk acceleration for its time. The automatic transmission, while lacking the driver control of a manual, provided effortless cruising, particularly on the highway. The gear ratios were optimized for comfortable highway speeds, but could feel somewhat sluggish during quick acceleration maneuvers. Compared to the more performance-oriented DeSoto Adventurer, the Firedome III prioritized comfort and refinement over outright speed. It also differed from potential future offerings with fuel injection or more advanced engine technologies.
Equipment & Trim Levels
The Firedome III Four-Door Sportsman was well-equipped for the late 1950s. Standard features included power steering, power brakes, a deluxe interior with cloth and vinyl upholstery, and a full-length chrome side molding. The dashboard featured a prominent instrument cluster with gauges for speed, fuel, temperature, and oil pressure. Optional extras included air conditioning, a radio, and whitewall tires. The interior trim was generally focused on providing a comfortable and luxurious experience for passengers, with ample space and supportive seating. The “Sportsman” designation indicated a slightly more upscale trim level compared to base Firedome models.
Chassis & Braking
The Firedome III rode on a traditional 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 this era. Braking was accomplished via drum brakes on all four wheels, measuring 305mm in diameter. While adequate for the time, the drum brakes lacked the stopping power of later disc brake systems. Steering was handled by a worm-reduction unit, which provided a relatively heavy but precise steering feel.
Market Reception & Comparison
The 1958 DeSoto Firedome III received generally positive reviews from automotive critics. It was praised for its stylish design, powerful engine, and comfortable ride. However, some critics noted that the car was relatively large and heavy, and that its handling was not as sharp as some of its competitors. Compared to other full-size American cars of the era, such as the Chevrolet Impala or the Ford Fairlane, the Firedome III offered a more luxurious and refined experience, but at a higher price point. Fuel economy, typical for the period, was not a strong suit, and maintenance costs could be substantial due to the car’s size and complexity.
Legacy
The DeSoto Firedome III, while a well-regarded car in its time, ultimately represents a chapter in automotive history marked by decline. DeSoto, as a brand, was discontinued by Chrysler in 1961 due to declining sales and increasing competition. Today, the 1958 Firedome III is a sought-after classic car, particularly among collectors of American automobiles. The 5.9-liter V8 engine, while not known for exceptional long-term reliability compared to some other engines of the era, is generally considered durable and relatively easy to maintain. Parts availability can be a challenge, but a dedicated network of classic car parts suppliers exists to support owners of these vehicles. The Firedome III stands as a testament to the bold styling and engineering of the late 1950s, and a reminder of a bygone era in American automotive history.
