Fred and August Duesenberg built aircraft and marine engines during World War I, and applied that engineering expertise to the design of racing engines and road cars. The Duesenberg Automobiles and Motors Company was incorporated in Delaware to manufacture and market the production car, while a separate organization, Duesenberg Brothers, built racing cars and engines. The Straight Eight was introduced publicly in late 1920 at the Commodore Hotel in New York City, but production delays pushed the first cars to customers until late 1921. Fred Duesenberg's decision to redesign the valvetrain — replacing horizontal overhead valves with a shaft-driven single overhead camshaft — and the relocation of the company's headquarters and factory from Newark, New Jersey to Indianapolis, Indiana were the primary causes of the delay.
The Straight Eight engine used a cast iron block with a detachable cast iron cylinder head featuring hemispheric combustion chambers and an aluminum lower crankcase. The crankshaft ran in three main bearings. A single updraft carburetor fed a mixture through the engine block to the intake manifold, with ignition provided by a Delco coil and breaker points. With a bore of 2.875 inches and a stroke of 5 inches, the engine displaced 260 cubic inches (4.3 litres) and produced 88 horsepower at 3,600 rpm with a five-to-one compression ratio, giving the car a top speed of approximately 71 miles per hour.
The chassis was built on a pressed steel ladder frame with semi-elliptic leaf springs and Watson Stabilator dampers at both ends. A tubular beam axle sat at the front and a live axle with radius rods at the rear. The standard wheelbase measured 134 inches, stretched to 141 inches for seven-passenger bodies. Center-locking wire wheels were fitted front and rear. The most technically significant feature was its Lockheed hydraulic braking system: front drums measured 16 inches in diameter and were finned to dissipate heat, with a glycerine-and-water fluid mixture in the system.
The car was sold as a rolling chassis, receiving a wide variety of coachbuilt body styles from outside coachbuilders. An unsynchronized three-speed gearbox, enclosed in a torque tube driving a spiral bevel rear axle, completed the drivetrain.
Initial production targets called for 100 cars per month, a figure the company never approached. By the end of 1922, after slightly more than a year in production, fewer than 150 Straight Eights had been delivered. Production continued through management changes and a receivership filing in January 1924, followed by a restructuring into the Duesenberg Motor Company in February 1925. E. L. Cord purchased the company in October 1926, ending production of the Straight Eight after approximately 650 units had been built.
The Duesenberg Straight Eight was succeeded in 1927 by the Model X, a slightly larger derivative built in very limited numbers — approximately twelve units — with an engine of the same bore and stroke but delivering 100 horsepower via a non-crossflow head. The far more famous Model J, introduced shortly after, effectively eclipsed the Straight Eight in public memory. The practice of naming the car the Model A came only retroactively, after the Model J arrived, and the original Straight Eight name under which it was sold largely faded from popular recognition.
Despite its relative obscurity, the Straight Eight's dual firsts — the overhead camshaft straight-eight in American series production and the first hydraulic four-wheel brakes on a production car — mark it as a genuine engineering landmark. The Duesenberg brothers' racing background infused the car with more mechanical sophistication than most American automobiles of the era, pointing toward the extraordinary Model J that would follow under Cord ownership.