The DeSoto Firedome III Four-Door Sportsman, specifically the 1958 facelifted model, represented a pinnacle of American automotive styling and power during the late 1950s. Produced from 1957 to 1958, it was positioned as a premium offering within the DeSoto lineup, slotting above the Firesweep and alongside the Adventurer. The Firedome III aimed to blend luxury, performance, and spaciousness, catering to families seeking a comfortable and stylish full-size sedan. This particular variant, equipped with the 5.9-liter V8 engine producing 295 horsepower, was a key component of DeSoto’s attempt to compete with rivals like Buick and Oldsmobile in the burgeoning post-war American car market.
Technical Specifications
| Brand | DeSoto |
| Model | Firedome |
| Generation | Firedome III Four-Door Sportsman (facelift 1958) |
| Type (Engine) | 5.9 V8 (295 Hp) |
| Start of production | 1957 |
| End of production | 1958 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 6 |
| Doors | 4 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 6.3 kg/Hp, 158 Hp/tonne |
| Weight-to-torque ratio | 3.5 kg/Nm, 283.3 Nm/tonne |
| 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 |
| Kerb Weight | 1867 kg, 4116.03 lbs |
| 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 (Back) 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 (turning diameter) | 15.1 m, 49.54 ft |
| Approach angle | 16.3° |
| Departure angle | 11.6° |
| Ramp-over (brakeover) angle | 10° |
| 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 | 3 gears, manual transmission |
| 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 Firedome III 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 simple design. It featured a cast iron block and cylinder heads, with an overhead valve (OHV) configuration. The engine utilized a single Carter carburetor, providing fuel delivery to the eight cylinders. The 10:1 compression ratio contributed to the engine’s respectable 295 horsepower output. The engine’s torque peak of 529 Nm (390 lb-ft) at 2400 rpm provided ample pulling power for the large sedan. The standard transmission was a three-speed manual, although a TorqueFlite automatic transmission was available as an option. The automatic, while offering convenience, did slightly diminish the overall performance compared to the manual version.
Driving Characteristics
The 1958 Firedome III with the 5.9-liter V8 and manual transmission offered a surprisingly spirited driving experience for a full-size American car of the era. Acceleration was brisk, and the engine provided a strong surge of power throughout the rev range. The three-speed manual gearbox, while not particularly sophisticated, allowed the driver to effectively utilize the engine’s torque. The automatic transmission, while smoother, resulted in a noticeable reduction in acceleration. Handling was typical for a large American sedan of the time – comfortable but not particularly sporty. The independent coil spring front suspension provided a reasonably compliant ride, while the leaf spring rear suspension offered stability but could be somewhat harsh over rough roads. The drum brakes on all four wheels were adequate for normal driving, but lacked the stopping power of more modern braking systems.
Equipment & Trim Levels
The Firedome III Four-Door Sportsman was well-equipped for its time. Standard features included a spacious interior with comfortable bench seats upholstered in durable cloth or vinyl. A full-width dashboard featured a prominent instrument cluster with gauges for speed, fuel level, coolant temperature, and oil pressure. Power steering and power brakes were optional extras, adding to the car’s convenience and ease of driving. Exterior trim included generous amounts of chrome, emphasizing the car’s luxurious character. Two-tone paint schemes were popular, adding to the Firedome III’s visual appeal. Available options included a radio, heater, air conditioning, and whitewall tires.
Chassis & Braking
The Firedome III rode on a sturdy body-on-frame chassis. The front suspension utilized independent coil springs, providing a more comfortable ride compared to the solid axle setups found on some competing models. The rear suspension employed leaf springs, offering a stable platform for carrying passengers and luggage. Brakes were drum brakes on all four wheels, providing adequate stopping power for the car’s weight. The steering system was a worm-reduction unit, offering relatively precise steering control. The car’s substantial weight (1867 kg or 4116 lbs) contributed to its stable handling but also limited its agility.
Market Reception & Comparison
The 1958 DeSoto Firedome III was generally well-received by automotive critics. It was praised for its stylish design, spacious interior, and powerful engine. However, some critics noted that the car’s handling was not as refined as some of its European competitors. Compared to other DeSoto models, the Firedome III offered a step up in terms of luxury and performance. The Firesweep, being the entry-level model, offered less power and fewer features. The Adventurer, positioned as DeSoto’s performance flagship, featured a more powerful engine and a sportier suspension. In terms of reliability, the DeSoto V8 engine was generally considered to be durable, but like all cars of the era, it required regular maintenance to prevent issues.
Legacy
The DeSoto Firedome III, despite its relatively short production run, remains a significant example of 1950s American automotive design. While DeSoto as a brand ultimately disappeared in 1961, the Firedome III continues to be appreciated by collectors and enthusiasts. The 5.9-liter V8 engine, while not known for exceptional fuel economy, proved to be a reliable and durable powerplant. Today, well-maintained examples of the 1958 Firedome III are sought after by those seeking a classic American car with a blend of style, power, and comfort. Parts availability can be a challenge, but a dedicated network of DeSoto enthusiasts and suppliers helps to keep these cars on the road.
