America entered the 1920s with its foot hard on the throttle. Prohibition didn’t slow the nation down; it rerouted its energy into back alleys, speakeasies, and a rapidly mechanizing underworld that understood mobility as power. In that environment, the automobile stopped being just transportation and became a strategic weapon, a status symbol, and a survival tool all at once.
The rise of the gangster automobile wasn’t accidental. It was the natural outcome of a country that had perfected mass production, paved its cities, and outlawed alcohol in one decisive stroke. Criminal empires now depended on speed, discretion, and mechanical reliability, and the car delivered all three in ways horses, trains, and even boats never could.
Prohibition Created a Market for Speed and Secrecy
When the Volstead Act took effect in 1920, it created a massive black market overnight. Bootleggers needed to move product quickly between distilleries, warehouses, and speakeasies while staying ahead of local police forces that were often underfunded and underpowered. The automobile, especially a powerful one, became the backbone of illicit logistics.
Early police cars were slow, poorly maintained, and frequently outmatched. A well-tuned V8 or high-displacement inline engine could simply outrun trouble, making mechanical advantage a matter of life and death. Speed wasn’t about thrill; it was about control of territory and survival under pressure.
The Automobile as an Extension of Power
By the mid-1920s, successful gangsters treated cars the way industrialists treated office towers. A vehicle communicated authority before a word was spoken, and nothing projected dominance like a large, expensive luxury car rolling silently to the curb. These machines offered space, comfort, and the kind of build quality that could absorb abuse without complaint.
Luxury cars also blended in. A high-end Cadillac or Packard didn’t attract suspicion in affluent neighborhoods or outside downtown hotels. That ability to appear legitimate was just as valuable as horsepower, allowing criminal figures to move openly through the same streets as bankers and politicians.
Technology Finally Caught Up With Ambition
The 1920s marked a turning point in automotive engineering. Electric starters eliminated the need for hand cranking, multi-cylinder engines delivered smoother and more predictable power, and improved suspensions made high-speed travel viable on imperfect roads. Hydraulic brakes were still evolving, but mechanical systems had become robust enough for aggressive driving.
Cadillac, in particular, stood at the intersection of innovation and excess. Precision manufacturing, interchangeable parts, and refined engines gave its cars a reputation for reliability that mattered far more to a bootlegger than marketing slogans. When everything depended on whether the car started, ran, and endured, engineering pedigree was not optional.
The Gangster Car Becomes a Cultural Symbol
As newspapers chronicled high-speed chases and street assassinations, the automobile became inseparable from the image of the American gangster. Cars were no longer passive objects in crime stories; they were active participants, shaping outcomes through speed, protection, and intimidation. The public absorbed this imagery quickly, and the gangster car became a symbol of modernity turned dangerous.
This cultural moment is where Al Capone’s 1928 Cadillac takes on deeper meaning. It was not just personal transportation, but a rolling expression of Prohibition-era America itself, where cutting-edge luxury, industrial power, and criminal enterprise collided on four wheels.
Why Cadillac Ruled the Luxury Market in the Late 1920s
By the time Al Capone specified his 1928 Cadillac, the brand was no longer just competing in the luxury market—it was defining it. Cadillac had spent the previous two decades proving that precision engineering and mass production were not mutually exclusive. That reputation carried enormous weight in an era when reliability was still a legitimate concern, even at the top end.
Luxury buyers in the late 1920s wanted more than plush interiors and imposing grilles. They demanded mechanical sophistication that justified the price and social prestige. Cadillac delivered both with a consistency that few rivals could match.
The V8 That Changed Expectations
Cadillac’s dominance began under the hood. The company had introduced its V8 engine as early as 1915, and by the late 1920s it was a thoroughly refined powerplant. In 1928, Cadillac’s 341 cubic-inch L-head V8 produced around 90 horsepower—strong numbers for the era, delivered with exceptional smoothness.
This mattered in daily use. The V8’s broad torque curve allowed a heavy Cadillac to accelerate effortlessly from low speeds, even when fully loaded. For drivers accustomed to the vibration and uneven power delivery of large sixes, the Cadillac V8 felt almost electric in its refinement.
Precision Manufacturing as a Status Symbol
Cadillac’s engineering advantage wasn’t just about raw power. The brand had built its identity around precision, famously winning the Dewar Trophy in 1908 for demonstrating fully interchangeable parts. By the late 1920s, this philosophy translated into engines that held tighter tolerances, quieter drivetrains, and fewer mechanical surprises.
For owners like Capone, this reliability had practical consequences. A car that started every time, ran cool under stress, and tolerated long hours of idling was more than convenient—it was essential. Cadillac’s reputation for mechanical consistency made it a logical choice for anyone whose schedule could not accommodate breakdowns.
Chassis, Ride Quality, and Road Authority
Cadillac also understood that luxury was experienced through motion. Its ladder-frame chassis was heavily built, prioritizing rigidity and durability over lightness. Semi-elliptic leaf springs were tuned for comfort, allowing the car to absorb rough urban pavement and uneven rural roads without unsettling occupants.
Steering was deliberate rather than quick, reinforcing a sense of control and stability at speed. On the open road, a Cadillac felt planted and confident, projecting authority through sheer mass and composure. This road presence became part of the brand’s identity, signaling wealth and power long before the car came to a stop.
Interior Craftsmanship and Customization
Inside, Cadillac matched its mechanical excellence with genuine craftsmanship. Interiors featured broadcloth or leather upholstery, deep carpeting, real wood trim, and thoughtful sound insulation. Controls were logically arranged, gauges were legible, and switchgear operated with a satisfying mechanical precision.
Equally important was Cadillac’s willingness to tailor cars to individual tastes. Buyers could specify body styles, finishes, and accessories, often through coachbuilders. This flexibility allowed figures like Capone to commission a vehicle that looked respectable while quietly accommodating unique requirements, blending luxury with discretion.
Brand Prestige Without Flash
Unlike some European luxury marques, Cadillac projected confidence without excess ornamentation. Its designs were formal, upright, and unmistakably American. That restraint helped Cadillac blend seamlessly into elite social environments, whether parked outside a hotel or cruising residential streets.
This balance of prestige and understatement was crucial in Prohibition-era America. A Cadillac communicated success and legitimacy, not ostentation. For someone navigating the thin line between public respectability and private criminal power, that image was invaluable.
Cadillac as the Default Choice of Power
By the late 1920s, Cadillac had become the luxury car people chose when failure was not an option. Industrialists, politicians, and underworld figures all gravitated toward the brand for the same reasons: engineering excellence, durability, and cultural authority. It was the car that suggested control over modern technology itself.
In this context, Al Capone’s 1928 Cadillac was not an indulgence—it was a strategic selection. The car embodied everything Cadillac represented at the height of its dominance, making it the perfect platform for both luxury and survival in an unforgiving era.
The 1928 Cadillac Model 341-A: Engineering, Chassis, and Powertrain Breakdown
To understand why Capone’s Cadillac was more than just a luxury conveyance, you have to start beneath the bodywork. The Model 341-A represented Cadillac at full technical stride, blending robust engineering with a level of refinement few rivals could approach in 1928. This was a machine designed to run hard, carry weight, and do so with near-silent authority.
The Heart of the Machine: Cadillac’s 341 Cubic-Inch V8
At the core of the Model 341-A sat Cadillac’s 341 cubic-inch V8, a 90-degree L-head design that traced its lineage directly back to the brand’s pioneering 1915 V8. Producing approximately 90 horsepower at modest engine speeds, it prioritized smooth torque delivery over outright revs. In an era when many luxury cars still relied on large straight-sixes, Cadillac’s V8 offered a decisive advantage in flexibility and refinement.
The engine’s long-stroke architecture delivered strong low-end pulling power, ideal for moving a heavy sedan from a standstill with minimal drama. This mattered in real-world use, especially when the car was loaded with passengers, armor, or additional equipment. Smoothness was a calling card, but durability was the hidden virtue that made the engine trusted by people who could not afford mechanical failure.
Cooling, Lubrication, and Reliability by Design
Cadillac engineers paid close attention to thermal and lubrication management, critical for a high-displacement V8 of the period. A large-capacity radiator and mechanically driven water pump ensured stable cooling even during prolonged idling or slow urban driving. The pressurized lubrication system fed oil reliably to bearings that lesser engines often starved under load.
This emphasis on reliability reflected Cadillac’s philosophy that luxury meant confidence. Owners were not expected to understand the mechanics, only to trust them completely. For Capone, that trust translated into a car that could idle quietly for long periods, then accelerate decisively without protest.
Transmission and Drivetrain: Controlled, Predictable Power
Power flowed through a three-speed manual transmission, equipped with synchromesh on the upper gears. This significantly reduced shift effort and gear clash, making the car easier to drive smoothly despite its size. The gearbox fed a torque tube driveshaft, enclosing the driveline and reducing vibration while adding structural rigidity.
The rear axle was engineered for quiet operation and long life rather than rapid gear changes. Cadillac understood that a luxury car should feel composed at speed, not busy or mechanical. The result was a drivetrain that felt calm and deliberate, reinforcing the car’s sense of command.
Chassis Construction: Strength Beneath the Silence
The Model 341-A rode on a substantial ladder-type steel frame, designed to resist flex under both weight and uneven road surfaces. Wheelbase options typically ranged around 140 to 145 inches, depending on body style, providing exceptional straight-line stability. This long, rigid foundation also made the car an ideal candidate for special bodies or reinforcements.
Suspension was conventional but well-executed, using semi-elliptic leaf springs at all four corners. Cadillac tuned spring rates for comfort without allowing excessive body motion, a delicate balance on the rough roads of late-1920s America. The ride was controlled, not floaty, reinforcing the car’s dignified demeanor.
Steering, Brakes, and Road Manners
Steering was handled by a worm-and-sector system, geared for stability rather than quick response. At speed, the car tracked confidently, requiring minimal correction, a trait prized on long drives and urban boulevards alike. Low-speed maneuvering demanded effort, but predictability mattered more than lightness in this class.
Braking came via four-wheel mechanical drum brakes, advanced for the era and carefully balanced for the car’s mass. While they lacked the outright stopping power of later hydraulic systems, they were progressive and reliable when properly maintained. For a heavy luxury sedan, this consistency was more important than raw braking force.
Electrical and Supporting Systems
A 6-volt electrical system powered ignition, lighting, and accessories, with Cadillac emphasizing reliability over novelty. Wiring was well-insulated, and components were conservatively rated, reducing failures in daily use. Even small details, such as generator output and starter motor strength, reflected an understanding of how these cars were actually used.
This was not experimental engineering. It was mature, proven technology executed at a high level. The Model 341-A didn’t seek attention for innovation; it earned respect through competence, which aligned perfectly with Cadillac’s brand promise and Capone’s practical needs.
Engineering as Strategy
Viewed as a whole, the Model 341-A was a carefully balanced machine: powerful without being temperamental, luxurious without being fragile. Its engineering reflected Cadillac’s belief that true prestige came from mastery of complexity, not showmanship. Every major mechanical decision favored control, durability, and composure.
For Al Capone, this meant his Cadillac was not just a status symbol, but a dependable tool shaped by the best American automotive thinking of the late 1920s. The car’s engineering made it an ideal platform for whatever lay ahead, whether that involved quiet respectability or far more dangerous realities.
Factory Luxury: Interior Craftsmanship, Comfort Features, and Prestige Details
With the mechanical foundation established, Cadillac turned its attention inward, where true luxury was measured not in flash but in execution. The interior of the 1928 Model 341-A was designed to reinforce the same themes found in its engineering: control, refinement, and permanence. Everything the driver and passengers touched was intended to feel deliberate, substantial, and beyond reproach.
Coachbuilt Standards Without Coachbuilt Excess
Cadillac interiors of this era were assembled with near coachbuilder attention to detail, even when built on the factory line. The wood garnish moldings were real hardwood, hand-finished and lacquered, not veneers applied for appearance alone. Joints were tight, surfaces smooth, and trim alignment was treated as a mark of craftsmanship rather than an assembly convenience.
Leather upholstery was thick, deeply grained, and stitched for longevity rather than softness alone. Seat cushions were generously sprung, using layered padding designed to absorb road vibration without collapsing over time. This was luxury built to endure daily use, not just impress during a showroom inspection.
Seating, Space, and Long-Distance Comfort
The sedan body style favored by Capone offered a tall roofline and upright seating geometry, prioritizing comfort and visibility. Front and rear seats were mounted high, improving outward sightlines in traffic while allowing occupants to sit naturally rather than reclined. Legroom was ample, particularly in the rear, reinforcing the car’s role as both a personal and chauffeured vehicle.
Ride comfort inside the cabin was enhanced by extensive insulation for the era. Felt, rubberized matting, and body padding reduced mechanical noise and road harshness, allowing the V8’s smoothness to define the driving experience. At speed, conversation could be maintained without raised voices, a subtle but critical marker of true luxury.
Instrumentation and Driver Environment
The dashboard layout reflected Cadillac’s philosophy of clarity over ornamentation. Large, easy-to-read gauges provided speed, engine temperature, oil pressure, and fuel level, all critical data for long-distance reliability. Switchgear was metal, not plastic, with a weighted, mechanical feel that reinforced confidence with every interaction.
The steering wheel itself was a substantial piece, typically finished in hard rubber or Bakelite, sized to provide leverage for low-speed maneuvering. Combined with the car’s predictable steering geometry, the driver environment felt composed and purposeful rather than indulgent. Cadillac expected owners to drive their cars, not merely be seen in them.
Heating, Ventilation, and Practical Amenities
While modern climate control was decades away, Cadillac offered thoughtful solutions for year-round comfort. Adjustable cowl ventilation allowed fresh air into the cabin without excessive wind buffeting. Optional heater systems, increasingly common by the late 1920s, extended the car’s usability through colder months, particularly important in northern cities like Chicago.
Interior lighting was soft and strategically placed, illuminating the cabin without glare. Storage pockets, robe cords, and assist straps were included not as novelties, but as acknowledgments of how the car would actually be used. These details reinforced Cadillac’s understanding of luxury as convenience rather than extravagance.
Prestige by Restraint
What ultimately set the Model 341-A apart was its restraint. There was no excessive ornamentation, no gilded surfaces or theatrical trim meant to impress from a distance. Prestige was conveyed through materials, silence, and the sense that nothing had been compromised.
For Al Capone, this interior sent a powerful message. It projected authority, taste, and permanence without inviting unnecessary attention. In an era where image was currency and discretion was survival, Cadillac’s factory luxury provided the perfect backdrop—quietly dominant, immaculately finished, and unmistakably American.
Capone’s Cadillac: Armoring, Bulletproof Glass, and Discreet Modifications
If the interior conveyed restraint, the real story of Capone’s Cadillac lived beneath the skin. This was not a factory armored car in the modern sense, but a carefully modified machine tailored for survival in a violent, unpredictable Chicago. The genius of the build lay in how thoroughly the protection was integrated without advertising its presence.
Early Armoring in a Pre-Standardized Era
Armoring a civilian automobile in 1928 was uncharted territory. There were no off-the-shelf ballistic solutions, no standardized threat ratings, and certainly no manufacturer-backed protection packages. Capone’s Cadillac relied on custom-fabricated steel plating installed behind door panels, under the roof structure, and along the firewall.
This steel added hundreds of pounds, though exact figures vary depending on the source and extent of coverage. What is certain is that the added mass pushed the chassis close to its practical limits. Cadillac’s robust ladder frame and conservative engineering margins made the modifications possible without immediate structural failure.
Bulletproof Glass: Thick, Heavy, and Imperfect
The most famous feature was the bullet-resistant glass. Period accounts describe laminated glass measuring roughly one inch thick, an extraordinary dimension for the era. This was not modern polycarbonate laminate, but layered safety glass designed to slow and deform handgun rounds rather than stop rifle fire outright.
The glass dramatically increased door and window weight, requiring reinforced regulators and careful alignment to prevent binding. Windows could still be lowered, but only partially and slowly, a compromise between security and practicality. Visibility suffered slightly due to distortion, yet this was an acceptable tradeoff in a world where ambush was a real concern.
Suspension, Brakes, and the Cost of Protection
All that extra weight had consequences. The stock semi-elliptic leaf springs were reportedly stiffened to compensate, raising ride height slightly and altering the car’s already deliberate handling. The Cadillac remained smooth, but its responses became more ponderous, especially during braking.
Mechanical drum brakes, already working hard on a nearly three-ton luxury car, now had even more mass to arrest. This reality underscores how protection in the late 1920s was always a balancing act. Survivability improved, but outright performance and emergency maneuverability were inevitably compromised.
Discretion Above All Else
Perhaps the most telling aspect of Capone’s Cadillac was how little it advertised its true nature. There were no external plates, no armored seams, no exaggerated trim to hint at what lay beneath. From the curb, it looked like any other well-kept Series 341-A driven by a prosperous businessman.
This discretion aligned perfectly with Capone’s public strategy at the time. He cultivated an image of legitimacy, attending charity events and presenting himself as a civic figure. A visibly armored car would have contradicted that narrative, signaling fear rather than confidence.
Government Seizure and Historical Irony
When federal agents finally seized the Cadillac in 1931, its hidden defenses became a matter of public record. The Treasury Department briefly used the car, recognizing the value of its protection during a period when federal officers themselves were targets. That irony is difficult to ignore: a gangster’s defensive engineering repurposed for law enforcement.
By then, the car had transcended its original role. It was no longer just Capone’s transportation, but a rolling artifact of Prohibition-era America. The modifications told a story of escalating violence, technological improvisation, and a luxury automobile pressed into service as both status symbol and survival tool.
A Rolling Statement of Power: How the Car Reflected Capone’s Public Image and Private Fears
By the late 1920s, Capone’s Cadillac had become more than protected transportation. It was a carefully engineered projection of authority, calibrated to send one message in public and a very different one in private. Every decision, from the base vehicle to the invisible armor, mirrored the dual reality of his life at the top of Chicago’s underworld.
Luxury as Legitimacy
Capone chose Cadillac because Cadillac defined American success in the interwar years. The Series 341-A represented cutting-edge prestige, with its smooth-running V8, long wheelbase, and a level of interior finish unmatched by most domestic rivals. Owning one placed Capone visually alongside industrialists, bankers, and politicians, not street-level criminals.
That association mattered. Cadillac marketed refinement, engineering excellence, and restraint, qualities Capone wanted reflected back at him in public. When he arrived at a hotel or theater, the car framed him as a powerful businessman accustomed to the best, not a man anticipating violence.
Mass, Presence, and Psychological Weight
Even without visible armor, a 1928 Cadillac carried immense physical presence. At nearly 5,000 pounds in stock form, with a tall beltline and upright greenhouse, it dominated the street simply by existing. The added weight of steel plating and bullet-resistant glass only reinforced that sense of immovability.
This mass worked on a psychological level as much as a mechanical one. The car projected inevitability, a rolling declaration that Capone was not someone to be rushed or intimidated. In traffic or at the curb, it asserted space the way its owner asserted control.
Hidden Armor and the Reality of Fear
Beneath the polished exterior, the Cadillac revealed Capone’s private understanding of his world. The concealed armor, thick glass, and reinforced structure were not expressions of bravado; they were acknowledgments of vulnerability. He knew that power in Prohibition-era Chicago was fragile and frequently contested.
The engineering compromises discussed earlier—slower responses, heavier braking, altered ride dynamics—were prices Capone was willing to pay. Survival mattered more than speed, and discretion mattered more than spectacle. The car was built to endure ambush, not to win a race.
A Car That Bridged Two Identities
Ultimately, Capone’s Cadillac functioned as a bridge between who he claimed to be and what he knew he was. Outwardly, it was a gentleman’s luxury sedan, aligned with Cadillac’s reputation for conservative excellence. Inwardly, it was a fortified capsule, shaped by constant threat and hard-earned paranoia.
That tension is what makes the car so historically compelling. It embodies the contradiction at the heart of Capone’s empire: immense public confidence underpinned by relentless private fear, all expressed through one of the most sophisticated American automobiles of its time.
Law Enforcement, Seizure, and the Car’s Afterlife in American History
The irony of Capone’s Cadillac is that its most consequential miles were driven after his empire began to collapse. The same car designed to insulate him from violence and scrutiny eventually became evidence of the state’s tightening grip. Once Capone was targeted through tax evasion rather than racketeering, the car’s fate shifted from private fortress to public artifact.
Federal Attention and the Limits of Protection
By 1931, Capone’s legal vulnerabilities had little to do with gunfire and everything to do with paper trails. Federal agents didn’t need to stop bullets; they needed to stop income streams. The armored Cadillac, no matter how advanced, was useless against accountants and prosecutors.
When Capone was convicted of tax evasion, the government seized many of his assets, including the Cadillac. Its armor, glass, and reinforcements were no longer symbols of untouchability. They became reminders that mechanical ingenuity could not outmaneuver federal law.
From Gangster Transport to Government Tool
In one of American history’s most striking reversals, the Cadillac reportedly entered service with the Treasury Department. Federal agents used the very car designed to protect a criminal kingpin as secure transportation during dangerous assignments. The car’s armor and mass, once meant to defy law enforcement, now served it.
This reuse was not theatrical symbolism; it was practical. In an era before purpose-built armored government vehicles, Capone’s Cadillac was among the most secure automobiles available. Its engineering outpaced official fleets, proving just how far private modification could exceed public resources in the late 1920s.
Mechanical Legacy Beyond Criminal Ownership
Stripped of its association with Capone, the Cadillac still stood as a technical milestone. Its V8, refined chassis, and structural integrity supported armor loads few manufacturers had anticipated. The car demonstrated the robustness of Cadillac’s engineering during a period when luxury brands were quietly solving problems of durability, not just comfort.
This unintended stress test reinforced Cadillac’s reputation. The fact that the chassis tolerated added weight without catastrophic failure spoke volumes about frame design, metallurgy, and suspension geometry of the era. Criminal use inadvertently validated Cadillac’s engineering philosophy.
Myth, Museum Life, and Cultural Immortality
Over time, the Cadillac transitioned from seized property to historical exhibit. Its survival allowed it to become a physical anchor for Prohibition-era storytelling, separating documented fact from gangster mythology. Unlike sensationalized vehicles of Hollywood invention, this car’s scars and modifications told a verifiable story.
Displayed in museums and referenced in serious historical work, the Cadillac became less about Capone himself and more about the America that produced him. It embodied a moment when industrial excellence, unchecked wealth, and weak regulation intersected. The car outlived its owner because it represented more than crime; it represented an era struggling to define power, authority, and modernity through machines.
Legacy and Myth: Separating Fact from Legend in Capone’s Infamous Cadillac
By the time Capone’s Cadillac entered the public imagination, it had already crossed the line from machine to symbol. That transformation blurred engineering reality with gangster folklore, creating a legend that often overshadows what the car actually was. To understand its true legacy, the myths have to be dismantled with the same precision Cadillac used to assemble it.
The Bulletproof Myth Versus Period Reality
Popular accounts often describe the Cadillac as completely bulletproof, as if it were a modern armored limo. In reality, the armor was selective and pragmatic, focused on glass and critical body sections rather than a fully reinforced shell. The laminated glass was thick for its time, but it was designed to defeat handgun rounds and small-caliber threats, not sustained rifle fire.
This distinction matters because it highlights how advanced the modifications were within 1928 constraints. Armor added hundreds of pounds, stressing springs, axles, and brakes never designed for combat duty. That the Cadillac remained functional under these conditions is impressive, but it was not invincible, and Capone knew it.
Ownership, Use, and the Limits of Documentation
Another enduring legend claims the car served as official transportation for top federal officials after Capone’s downfall. While the Cadillac was indeed seized and evaluated by authorities, definitive records tying it to routine presidential use are thin. What is clear is that law enforcement recognized its protective value at a time when government fleets lagged behind private engineering.
This ambiguity feeds the myth, but it also reinforces the point. The mere plausibility of federal reuse speaks volumes about how advanced the car was relative to institutional resources. In the late 1920s, the line between criminal ingenuity and state capability was uncomfortably narrow.
Hollywood Distortion and Cultural Reinvention
Film and television amplified the Cadillac’s menace, often exaggerating its armor, speed, and invulnerability. On screen, it became a rolling fortress, a visual shorthand for Capone’s power and paranoia. The real car was subtler, more mechanical, and more interesting as a product of American industry rather than cinematic excess.
This distortion has had a side effect. It shifted focus away from Cadillac’s role as an engineering leader and toward Capone as a mythic figure. The car’s true importance lies not in how terrifying it looked, but in how competently it was built.
What the Cadillac Ultimately Represents
Stripped of legend, Capone’s 1928 Cadillac stands as a stress test of American luxury engineering in the pre-war era. It proved that a premium chassis, properly engineered, could absorb extreme modification without collapsing under the load. That capability helped cement Cadillac’s dominance and foreshadowed the future of armored executive transport.
The final verdict is clear. This Cadillac matters not because a gangster owned it, but because it revealed how advanced American automotive engineering had become by the late 1920s. Capone’s infamy may have preserved the car, but Cadillac’s engineering excellence is what gave it lasting historical weight.
