Image of 1946 Buick Roadmaster Series 70, Note: These illustrations use artistic license and may differ from actual historical models.

Engine Specifications
Engine:	Straight 8
Displacement:	320.2 cu in (5.2 L)
Horsepower:	144 hp
Torque:	277 lb-ft
Compression Ratio:	6.6:1
Ignition System:	Battery Ignition
Cooling System:	Liquid Cooled
Performance Specifications
0-60 Time:	Estimated 15 seconds
1/4 Mile Time:	Not available
Top Speed:	90 mph
Transmission and Drive
Drive Type:	Rear Wheel Drive
Transmission Type:	3-speed manual
Fuel and Efficiency
Fuel System Type:	Carburetor
MPG:	Estimated 15 mpg
Dimensions and Brakes
Brakes:	Drum Brakes
Wheelbase:	129 inches
Weight:	4,200 lbs

1946 Buick Roadmaster Series 70: A Postwar American Flagship

The 1946 Buick Roadmaster Series 70 brought prewar luxury back to American roads with a long hood, a powerful straight-eight engine, and the unmistakable presence of a full-size Buick. Built by the Buick Motor Division of General Motors, the Roadmaster sat near the top of Buick’s range, offering more size, power, and finish than the brand’s more affordable models.

Its return came at a pivotal moment. During World War II, U.S. automakers stopped building civilian cars and turned their factories to wartime production. When Buick resumed automobile production, it needed to get cars into showrooms quickly. The 1946 Roadmaster was therefore closely related to the prewar design rather than an entirely new postwar car. That makes it a fascinating bridge between the elegant automobiles of the late 1930s and the broader, more modern designs that followed.

One notable detail is that the Roadmaster’s celebrated Dynaflow automatic transmission was not yet available. Buick introduced Dynaflow in 1948, so the 1946 model relied on a conventional three-speed manual transmission. Its reputation for effortless cruising came from the big engine and smooth suspension, not from an automatic gearbox.

Roadmaster Styling and Body Styles

The Series 70 looked every inch a premium American car. Its broad, upright grille was framed by substantial chrome, while flowing front fenders blended into a long, substantial body. Buick’s signature porthole-style fender vents, usually called “VentiPorts,” emphasized the car’s length and gave it an unmistakable profile. The hood stretched out ahead of the driver, and generous brightwork made the Roadmaster look formal without being overly delicate.

Buick offered the Roadmaster in several body styles, including a four-door sedan, a two-door Sedanette with a sweeping fastback roof, a convertible, and an Estate Wagon. The Sedanette is one of the most visually distinctive versions, with a roofline that flows smoothly into the rear bodywork. The convertible has the open-air glamour many people associate with classic Buicks, while the wood-bodied Estate Wagon is the standout choice for collectors seeking something less common.

Paint choices varied by body style and production details, but buyers could choose from the rich, sober colors popular in the period, including dark blues, greens, maroons, grays, and black. Dark, glossy finishes suited the Roadmaster’s formal character, while lighter colors could make its broad fenders and chrome trim stand out. Exact paint names and availability should be confirmed using a factory color chart for the specific model and build date.

A Spacious, Carefully Finished Cabin

The Roadmaster’s cabin was designed for comfort on long drives. Its wide bench seats, generous legroom, and upright seating position gave passengers room to settle in, while the large windows provided excellent visibility by the standards of a car this size. Cloth upholstery was common in closed models, with richer materials and trim used to reinforce the Roadmaster’s position above Buick’s lower-priced lines. Convertible interiors could feature leather, and Estate Wagons added distinctive woodwork to their cargo-area design.

The dashboard was straightforward and substantial, with clear instruments and neatly arranged controls. Depending on the car’s equipment, buyers could have conveniences such as a radio, heater, clock, and upgraded trim. These were desirable amenities, but the Roadmaster remained a product of its era: there was no modern climate control, electronic infotainment, or power-assisted steering. Its appeal came from space, materials, mechanical smoothness, and a feeling of solid construction.

Engineering Before the Automatic Era

At the heart of the 1946 Roadmaster was Buick’s 320.2-cubic-inch Fireball straight-eight. It produced about 144 horsepower and delivered its power with the relaxed, low-revving character expected of a large luxury car. A three-speed manual transmission was standard, and the engine drove the rear wheels. The Roadmaster also used hydraulic brakes and a coil-spring suspension system that helped distinguish Buick’s ride from that of many rivals using more traditional spring arrangements.

The car’s engineering was not a wholesale technological revolution in 1946. Instead, Buick combined proven prewar mechanicals with the comfort and upscale equipment expected of a premium postwar automobile. That practical approach allowed the company to return to civilian production while keeping the Roadmaster familiar, capable, and appealing to buyers eager for a new car after years of shortages.

Historical Significance and Buick’s Identity

The Roadmaster helped define Buick as a maker of substantial, well-appointed cars that sat between mainstream and luxury brands. It was more accessible than the most expensive American prestige cars, yet its size, chrome detailing, engine, and interior finish gave it a distinctly upscale presence. For buyers who wanted a commanding automobile without stepping up to Cadillac, the Roadmaster was a compelling choice.

Its significance also lies in its timing. The 1946 model represents the hurried but important restart of the American auto industry after wartime restrictions. Its familiar shape reflects the immediate postwar reality: manufacturers had a huge public appetite for cars, but little time to develop completely new ones. As a result, the Roadmaster preserves a strong connection to prewar design while pointing toward the larger, more elaborate postwar cars Buick would soon introduce.

The model’s influence was less about one breakthrough feature and more about a successful formula: a large, smooth straight-eight, a comfortable chassis, expressive styling, and a strong sense of value within the premium market. Buick continued to refine that combination in later Roadmasters, including the 1948 introduction of Dynaflow.

Performance, Ride, and Driving Feel

With roughly 144 horsepower moving a heavy, full-size body, the 1946 Roadmaster was built for relaxed progress rather than quick acceleration. Period condition, gearing, tires, and road surface all affect performance, but a sound example is generally estimated to reach 60 mph in roughly 16 to 19 seconds. Top speed is commonly placed around 90 to 95 mph, though that is a theoretical figure for a well-maintained car, not a speed at which most owners would want to cruise today.

On the road, the straight-eight delivers a deep, even mechanical hum. It does not have the sharp exhaust note of a performance car. Instead, the engine feels smooth and unhurried, with its strongest impression coming from steady pulling power and the way it gathers speed without drama. The three-speed manual requires deliberate clutch and shift work, so the driver is more involved than in a later Buick equipped with Dynaflow.

The suspension is tuned for comfort. It softens ordinary bumps and gives the car a gentle, floating quality, although the Roadmaster’s size and age mean that worn shocks, tired springs, loose steering components, or old tires can make it feel less composed. On winding roads, it is best driven smoothly and with room to maneuver. Crosswinds and uneven pavement can be felt through the broad body, and its weight and vintage brakes call for more planning than a modern car demands.

Ownership, Maintenance, and Reliability

Today, most 1946 Roadmasters are used as show cars, weekend cruisers, parade vehicles, or occasional touring cars. A well-sorted example can cover local roads comfortably, but its age, fuel consumption, braking distances, and limited safety equipment make it a poor choice for routine modern commuting. The sedan is generally the most practical body style; convertibles and Estate Wagons are often treated as collectible specialty cars.

Mechanical repairs are approachable for an experienced hobbyist because the car uses comparatively simple, non-electronic systems. The straight-eight is durable when maintained, but parts availability, specialist knowledge, and access to machine work matter when an engine needs major rebuilding. Routine attention includes checking the cooling system, ignition, carburetor, lubrication, hydraulic brakes, and electrical connections. The braking system deserves particular care: decades-old hoses, wheel cylinders, and master cylinders should be inspected or renewed before regular driving.

Restoration can become expensive, especially when chrome needs replating, interior materials require custom work, or a rare Estate Wagon needs wood restoration. A car that looks attractive in photographs may still need substantial mechanical and structural attention, so an inspection by someone familiar with prewar and early postwar Buicks is worthwhile.

Notable Facts and Common Criticisms

The 1946 Roadmaster’s most unusual version is the Estate Wagon. Its traditional wood-bodied construction and low production relative to the sedans make it especially desirable today. The Sedanette is another memorable body style, pairing a streamlined roof with the Roadmaster’s formal, full-size proportions.

A reasonable estimate for total 1946 Series 70 production is around 80,000 to 85,000 cars, though exact totals depend on how production records are grouped. That makes ordinary sedans findable compared with many low-volume classics, but it does not mean every body style is common. Convertibles are scarcer, and Estate Wagons are considerably harder to locate in sound, complete condition.

Common criticisms are familiar to anyone considering a car from the 1940s: fuel economy is modest, the controls require a learning curve, and the handling and braking feel dated beside a modern vehicle. The Roadmaster is also large for narrow streets and compact garages. Its prewar-based styling may seem conservative to someone expecting a completely new design for 1946, but that continuity is part of its historical character.

1946 Buick Roadmaster Values and Rarity

Collector values vary sharply with body style, originality, restoration quality, and mechanical condition. As a broad 2026 estimate in U.S. dollars, a project or rough sedan might sell for about $8,000 to $18,000. A usable driver or solid older restoration could fall around $18,000 to $35,000, while a high-quality restored sedan may bring roughly $35,000 to $60,000. Excellent convertibles and Estate Wagons can command approximately $60,000 to $120,000 or more, with exceptional examples sometimes exceeding that range.

These are general market estimates, not guaranteed sale prices. A documented, correctly restored car with strong bodywork and an excellent interior will usually attract more interest than a modified or incomplete example. The sedan is the easiest body style to find, while the convertible and especially the Estate Wagon are much rarer on the open market.

Values for the Roadmaster tend to be strongest for the rare body styles and the best restorations. Ordinary sedans have generally been more price-sensitive, and market prices can vary by region and condition. Over the long term, top-quality convertibles and wagons have the best prospects for maintaining collector demand, though restoration costs can rise faster than resale values. Buyers should focus on condition and originality rather than assuming every example will appreciate quickly.

Why the 1946 Roadmaster Still Matters

The 1946 Buick Roadmaster Series 70 combines the smooth power of a large straight-eight with the comfort, scale, and brightwork that made postwar American cars famous. It is historically important as a link between prewar Buick design and the more modern models that followed, and its range of body styles gives collectors several distinct ways to enjoy the nameplate.

Whether seen in a stately sedan, a sleek Sedanette, an open convertible, or a rare wood-bodied Estate Wagon, the Roadmaster makes a strong case for the virtues of the classic American cruiser. It is not quick by modern standards, but it was never meant to be. Its lasting appeal is the experience of traveling in a roomy, carefully finished Buick that carries an important piece of the postwar story.