Image of 1940 Buick Roadmaster Series 70, Note: These illustrations use artistic license and may differ from actual historical models.

Engine Specifications
Engine Options:	Straight 8
Displacement Range:	320.2 cu in (5.2 L)
Horsepower Range:	141 HP
Torque:	269 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 10-12 MPG
Dimensions and Brakes
Brakes:	Drum Brakes
Wheelbase:	133 inches
Weight:	4,000 lbs

1940 Buick Roadmaster Series 70: Buick’s Prewar Flagship

The 1940 Buick Roadmaster Series 70 brought big-car presence and genuinely modern engineering together in one polished package. Built by Buick, a division of General Motors, the Roadmaster sat near the top of the company’s range, above the Special, Super, and Century. It was aimed at drivers who wanted a substantial, well-appointed American automobile with the power and refinement to cover long distances in comfort.

Its timing gives it a special place in Buick history. The Roadmaster was a prewar luxury car built just before World War II redirected American factories toward military production. One intriguing detail is that Buick’s 1940 lineup included the newly introduced Super, while the Roadmaster remained the marque’s largest and most prestigious regular-production car. Its long hood, broad cabin, and confident styling made its status unmistakable.

Roadmaster Styling: Broad Shoulders and a Bold Grille

Buick’s 1940 design looked more integrated and streamlined than the upright cars of the early 1930s. The front end was dominated by a substantial, vertically accented grille, framed by rounded front fenders. Headlamps were set into the fenders rather than perched separately beside the hood, giving the nose a cleaner, more modern appearance. A long bonnet, bright trim, and sculpted fender lines added visual weight without making the car look clumsy.

Many Roadmasters were fitted with running boards, a feature that still linked the car to older styling conventions. Yet the body’s overall proportions were moving toward the smoother, more unified forms that would define American cars in the postwar years. The Roadmaster’s substantial wheelbase and broad stance also helped distinguish it from smaller Buicks.

A Comfortable Cabin with Buick-Level Finish

Inside, the Roadmaster was designed for relaxed touring rather than stripped-down utility. Depending on body style and specification, passengers found wide seating, generous legroom, quality cloth upholstery, carefully finished trim, and a substantial dashboard with clear instrumentation. Woodgrain-style accents and bright detailing added a formal touch, while the roomy cabin made the car comfortable for family travel or business trips.

Buyers could equip their cars with period conveniences such as a radio and heater, though equipment varied by car and market. Buick also offered accessories and trim choices that let owners personalize the cabin. Materials and construction were a selling point: this was a premium Buick, built to feel more substantial than an economy-minded family sedan.

Body Styles and Period Colors

Roadmaster buyers could choose from several body configurations, with availability varying by model designation. The range included practical closed-body sedans as well as more stylish two-door models, and Buick offered open-car choices such as convertible forms. The four-door sedan was a natural choice for owners who prioritized passenger space and everyday usability. For collectors, the open Roadmaster and sleek two-door versions tend to draw the most attention because they combine the car’s imposing proportions with a more distinctive profile.

Factory paint selections changed over time and could vary by catalog and production details. Period Buick colors included restrained dark shades alongside blues, greens, grays, and lighter tones. Black and deep, formal colors suited the Roadmaster’s executive character, while brighter colors could bring out the curves of its fenders and grille. When evaluating a restored car, check its paint code and documentation rather than assuming a color is original based on appearance alone.

Engineering Ahead of Its Time

Power came from Buick’s large 320.2-cubic-inch inline-eight, rated at about 141 horsepower. The engine was paired with a three-speed manual transmission, typically with synchromesh action, and Buick’s smooth-running straight-eight design gave the Roadmaster the relaxed torque expected of a luxury car. It was not a high-revving sports engine. Its strength was steady, quiet pulling power.

Buick had also invested in independent front suspension, introduced on its cars earlier in the decade. That setup helped the front wheels respond more independently to bumps than a traditional solid front axle. The Roadmaster combined it with a sturdy frame and a conventional rear-drive layout, producing a car that felt advanced for its period while remaining mechanically familiar to a competent mechanic.

It is worth separating 1940 technology from later Buick innovations. The famous Dynaflow automatic transmission did not arrive until after the war, in 1948. A 1940 Roadmaster was a manual-transmission car, so its driver had to operate the clutch and shift gears.

Performance and the Roadmaster Driving Feel

With roughly 141 horsepower, the Roadmaster had strong performance for a full-size luxury car of its day. Period gearing, vehicle condition, body style, and passenger load all affect the numbers, but a healthy example may reach approximately 85 to 95 mph. A reasonable estimate for 0-to-60-mph acceleration is around 16 to 19 seconds. These are period-car estimates, not modern instrumented-test figures, and an original car should not be pushed to its limits without first checking its mechanical condition.

On the road, the inline-eight delivers a deep, even hum that becomes more noticeable under acceleration but is generally smoother than the sound of many smaller engines. The long wheelbase helps the car settle over ordinary road imperfections, while its weight and soft suspension favor comfort over quick responses. On a winding road, the Roadmaster asks for deliberate steering and measured cornering. It can manage a crosswind or uneven pavement, but its size and age mean it does not feel like a modern car with power steering, disc brakes, or contemporary tires.

The driving experience is part of the appeal: a large steering wheel, a manual gear change, and a broad view over the hood put the driver in direct contact with the machine. The car feels most at home on an open highway, moving at a comfortable cruising pace rather than darting through traffic.

What the Roadmaster Contributed to Buick Design

The Series 70 showed how a luxury car could retain traditional American size while adopting a more unified, streamlined body. Its fender-integrated headlamps, smoother contours, and carefully balanced proportions helped move Buick away from the more separate, upright forms of earlier decades. The Roadmaster did not invent streamlined automotive design, but it translated that design direction into a prestigious, usable Buick.

Its engineering also reflected an important shift in expectations. Independent front suspension and a powerful straight-eight helped make comfort and performance partners rather than opposites. Against many contemporaries, the Roadmaster stood out for its combination of room, smoothness, and upscale finish. Its influence is best understood as part of Buick’s broader evolution toward quieter, more comfortable, and more integrated automobiles.

Ownership, Maintenance, and Reliability

Today, a 1940 Roadmaster is most commonly enjoyed as a show car, touring car, or weekend classic. A carefully maintained example can make local outings and club events, but using one as a daily driver is less practical. Its fuel economy, size, vintage braking and lighting systems, and limited protection by modern standards all call for realistic expectations.

The straight-eight is generally serviceable for a specialist or an experienced hobbyist, and its basic mechanical layout is understandable by classic-car standards. The challenge is often less about complicated electronics and more about finding correct parts, sourcing trim, and undoing decades of wear or improvised repairs. Before buying, inspect the frame and body for corrosion, check the engine’s oil pressure and cooling system, test the clutch and transmission, and examine the brakes, wiring, and suspension. A pre-purchase inspection by a mechanic familiar with prewar Buicks is money well spent.

Roadmaster Trivia and Common Criticisms

The 1940 Roadmaster belongs to the last generation of Buicks built before wartime production reshaped the American auto industry. Buick passenger-car production stopped during the war years, making prewar cars like this a tangible link to the industry’s transition. The Roadmaster is not especially known for a single speed or endurance record; its reputation rests more on comfort, size, and Buick’s engineering than on competition success.

There is no single celebrity ownership story that defines the model. Its period appeal was broader: it suited well-to-do families and professionals who wanted an imposing American car. Common criticisms today are practical ones. The Roadmaster is heavy, thirsty by modern standards, and less nimble than smaller classics. Its vintage brakes and steering also demand more attention from the driver than modern systems do.

Collector Values and Availability

A reasonable production estimate for 1940 Roadmasters is roughly 18,000 cars across the Series 70 range, though published totals can vary depending on how model and body-style figures are grouped. That makes the Roadmaster uncommon today, but not impossibly rare. Closed-body cars appear more often than the most desirable open and specialty versions, and original trim, sound structure, and documented restoration history can make a major difference in value.

As a broad 2026 market estimate, a project or rough-running sedan might sell for about $10,000 to $20,000. A usable driver could fall around $20,000 to $35,000, while a very good restored sedan may bring roughly $35,000 to $55,000. Desirable convertibles and especially well-restored examples can reach approximately $60,000 to $100,000 or more. These are general ranges, not appraisals: condition, body style, originality, provenance, and the quality of the restoration matter greatly.

Values for prewar classics tend to be selective rather than uniformly rising. Exceptional cars with strong documentation remain appealing, but restoration costs can exceed the market value of an ordinary sedan. Buyers should focus on condition and the quality of the work, not simply on the idea that every old luxury car will appreciate.

Why the 1940 Roadmaster Still Matters

The 1940 Buick Roadmaster Series 70 combined a smooth straight-eight, independent front suspension, generous passenger space, and distinctive prewar styling in a car built for comfortable travel. It was large and formal, yet more streamlined than the older cars it followed. Today, its best examples reward careful owners with an engaging glimpse of Buick at the height of its prewar confidence. The Roadmaster’s real legacy is not just its size or its chrome, but the way it made American luxury feel both powerful and ready for the modern road.