Quick Facts

The following table concentrates on specifications that are consistently associated with the DA chassis and Sport Roadster. Body catalogs and surviving registration records can differ in terminology, particularly where roadster and Sport Roadster descriptions are concerned.

The DA designation is the essential family identifier. It separates the car from Dodge's earlier Standard Six, Victory Six, and Senior Six lines, as well as from the later Dodge series introduced as Chrysler rationalized its model range.

Why the DA Sport Roadster Matters

The Sport Roadster demonstrates how rapidly six-cylinder power and hydraulic braking moved into ordinary American cars before the Depression altered the market. Dodge had used hydraulic brakes before many mass-market rivals, and the DA retained that practical advantage when Chevrolet introduced its overhead-valve six and Ford continued with the four-cylinder Model A.

The open body also preserves a form that disappeared quickly as buyers moved toward enclosed coupes and sedans. A DA sedan provided better weather protection and family utility, but the Sport Roadster traded those qualities for a folding top, separate rear seat, and cleaner rear deck. Attrition was correspondingly severe because open cars were exposed to water, body damage, repurposing, and decades of incomplete storage.

Its importance is not tied to a competition record or a high-compression engine. It comes from the combination of a durable side-valve six, a conventional separate chassis, hydraulic service brakes, and one of the least utilitarian bodies available in the DA range.

Historical Context and Development

By the time the DA appeared, Dodge Brothers had changed profoundly. Founders John and Horace Dodge had died in 1920, the company passed through investment ownership, and Chrysler purchased it in July 1928. Dodge brought Chrysler substantial manufacturing capacity, an established dealer organization, and a reputation built partly on robust engineering.

The DA was developed for a market in which six-cylinder engines were becoming a major sales argument. Chevrolet's 1929 International Series AC advertised overhead valves and six cylinders at a mass-market price, while the Ford Model A relied on a simpler 201-cubic-inch four. Essex and other medium-priced manufacturers also competed for customers who wanted smoother power without entering the expensive-car class.

Dodge answered with displacement and conservative mechanical design rather than an exotic cylinder head. The DA engine used side valves in the block, a single carburetor, and modest compression suitable for contemporary gasoline. Four-wheel hydraulic brakes and a 112-inch wheelbase gave the chassis specifications that were credible beyond the lowest-priced field.

Design and Coachwork

The Sport Roadster's visual character comes from its long hood, upright radiator shell, separate front fenders, exposed running boards, and compact passenger compartment. The folded top sits low behind the front seat, while the rumble-seat lid forms much of the rear deck. A split or folding windshield, body-color panels, bright radiator trim, and period artillery or wire-wheel equipment can materially change the appearance of a restored example.

DA bodies were produced when Dodge's association with steel body construction was already well established. Even so, restoration should never assume that an open body contains no wood. Tack strips, top mounting points, seat structures, and local reinforcing pieces can deteriorate, and old repairs often conceal damage around the doors and rear body tub.

The Sport Roadster was not a homologation model, nor did Dodge create it as a factory racing special. Its sporting description referred primarily to body configuration and equipment rather than a separate high-output engine or competition chassis.

Engine and Drivetrain

The DA's six-cylinder engine is a cast-iron, side-valve design with the intake and exhaust valves operating in the block. Its 3.25-inch bore and 4.1875-inch stroke produce approximately 208 cubic inches, and period specifications commonly list 63 horsepower. The long stroke and low compression favored useful low-speed torque and smooth operation rather than sustained high engine speed.

A single downdraft or updraft carburetor description can depend on the exact carburetor application and source being consulted, so the unit fitted to an individual car should be checked against its casting and model number. Fuel delivery was conventional for the period, while battery-and-coil ignition used a distributor, points, condenser, and spark plugs. A generator supplied the six-volt electrical system.

Pressurized engine lubrication, a belt-driven fan, a water pump, and a cellular radiator addressed the DA's basic oiling and cooling requirements. The transmission is a floor-shifted three-speed manual driving a live rear axle through an enclosed or partially enclosed driveline arrangement typical of the period. Synchromesh should not be assumed, and deliberate double-declutching reduces gear clash during downshifts.

These are the principal factory mechanical dimensions useful when evaluating an engine advertised as DA-correct.

Published compression ratios and carburetor applications are not consistent across surviving general-reference material, and replacement carburetors are common. A restoration should be based on the engine number, original parts-book application, and dated factory literature rather than a specification copied from a later interchange manual.

Chassis, Suspension, and Braking

The DA uses separate body-and-frame construction. A pressed-steel ladder frame carries the engine, transmission, body, and suspension, while beam axles and longitudinal semi-elliptic leaf springs provide straightforward wheel control. Lever or friction-type dampers, depending on equipment and replacement history, supplement the springs.

Steering is by a manual steering box acting on the solid front axle through conventional drag-link and tie-rod hardware. Worn kingpins, steering-box bushings, spring shackles, and tie-rod joints can combine to create wander, even when no single component appears dramatically loose.

Dodge's four-wheel hydraulic brakes are a defining DA feature. They are mechanically simple by later standards, but successful operation depends on sound wheel cylinders, hoses or lines, a properly rebuilt master cylinder, correctly arced shoes, dry linings, and round drums.

The table records chassis details that apply broadly to the DA Sport Roadster without forcing uncertain body measurements into the record.

A properly rebuilt DA chassis should track predictably at period road speeds. Excessive shimmy, violent brake pull, or several inches of uncontrolled steering movement indicates wear or poor adjustment, not an unavoidable trait of the model.

Driving Experience and Handling Dynamics

The long-stroke six delivers its best work at low and moderate engine speeds. Throttle response is measured rather than sharp, but the engine should pull cleanly once the carburetor, ignition advance, and valve clearances are correct. Persistent hesitation often points to a vacuum leak, restricted fuel supply, weak ignition, or incorrect carburetor setup.

At parking speed the steering is heavy, particularly if the tires are underinflated or the steering box is adjusted too tightly. Once moving, the large wheel provides leverage and the car responds with a steady, deliberate action. A sound front axle should not hunt continuously across the road.

The leaf-sprung chassis permits visible body movement over undulating surfaces, although the Sport Roadster's comparatively compact body avoids some of the mass of a sedan. Grip is governed by narrow cross-ply tires, limited damping, and the geometry of solid axles. Smooth inputs preserve stability far better than abrupt steering or braking.

The non-synchronized transmission rewards patience. First gear gets the car moving, second covers much of the useful acceleration range, and top gear lets the six settle into an easy cadence. Hydraulic drums provide progressive stopping when dry and correctly adjusted, but they lack the heat capacity and repeated-stop consistency of later systems.

Identification and Originality

A genuine DA Sport Roadster should first be established as a DA chassis, then as an authentic open body rather than a sedan chassis carrying a later reproduction or converted body. Inspect the serial plate, frame markings where present, engine stamping, body tags, registration documents, and old photographs as a group. Plate location and numbering practice can differ with assembly plant and production date, so unsupported internet decoding charts should not overrule factory records or recognized Dodge club references.

Serial, Engine, and Body Evidence

Early Dodge vehicles do not always satisfy the modern expectation that the chassis, engine, and body carry one identical number. The useful question is whether each number falls within the correct DA sequence and whether the components could plausibly have been assembled together. An engine changed during the car's working life may be mechanically correct but should not be represented as original without documentation.

Check for disturbed rivets, newly stamped characters, mismatched typefaces, and a serial plate that appears much newer than its surroundings. State-issued identification numbers are not proof of fraud, but they require a clear documentary explanation because older cars were sometimes titled by engine number and later renumbered after an engine replacement.

Body and Equipment Clues

The cowl, doors, windshield stanchions, rear deck, rumble-seat opening, top irons, and floor structure should form a coherent assembly. Converted coupes and newly constructed roadster bodies can be attractive, but they do not carry the same originality as a surviving factory Sport Roadster body. Measure panel symmetry and examine inner seams before accepting fresh paint as evidence of sound coachwork.

Radiator shells, headlamps, bumpers, instruments, steering wheels, wheels, hubcaps, carburetors, distributors, and generators were frequently replaced. Parts from adjacent Dodge series may fit or look convincing while differing in dimensions, mounting details, or finish. Factory parts books, accessory catalogs, and period photographs are indispensable when resolving these distinctions.

Paint, Trim, and Matching Numbers

Dodge offered named color combinations rather than modern standardized paint codes of the kind familiar from postwar cars. A responsible restoration should work from period color cards, protected original paint, sales literature, and physical evidence beneath trim or hardware. Bright modern metallic finishes, incorrect gloss levels, and generic vinyl upholstery can materially alter the appearance of a DA roadster.

Date-coded components are less comprehensive than on later collector cars, but casting marks, supplier tags, patent plates, and accessory markings still help establish age. Claims of matching numbers should specify exactly which stampings and documents were compared.

DA Six Variant and Body-Style Breakdown

Dodge sold the DA as a family of open and closed cars using the same basic six-cylinder chassis. Catalog offerings changed during the production run and by market, so the table concentrates on principal body forms rather than assigning unsupported production totals or body codes.

There was no documented factory high-performance Sport Roadster engine separate from the normal DA unit. Wire wheels, side-mounted spare equipment, bumpers, lighting hardware, and trim can affect presentation, but an accessory does not convert another body style into a Sport Roadster.

Performance and Dimensional Specifications

Standardized acceleration and top-speed testing was not routinely published for every early body style, and body weight, axle ratio, road surface, and test method could produce substantial differences. It is more useful to preserve the documented factory dimensions than to assign a modern-looking 0-to-60-mph figure that cannot be supported.

Period references are not sufficiently consistent to assign one definitive Sport Roadster curb weight, maximum speed, quarter-mile time, or axle ratio to every car. Tire size and gearing should be verified from the build configuration, parts book, and components fitted to the individual vehicle.

Compared With Related Dodge Models

DA Six Versus the Standard Six

The earlier Standard Six belongs to a different Dodge series and should not be identified as a DA merely because both use side-valve six-cylinder engines. Chassis dimensions, engine details, radiator treatment, body hardware, and serial sequences must all be checked. This distinction becomes particularly important when an older restoration contains mixed parts.

DA Six Versus Victory Six and Senior Six

The Victory Six and Senior Six represented separate Dodge lines with their own engines, chassis dimensions, bodies, and market pricing. Their components can resemble DA pieces in photographs, but interchangeability and visual similarity are not proof of correctness. A Senior Six engine or radiator shell on a DA chassis changes both authenticity and service requirements.

DA Six Versus the Ford Model A and Chevrolet Six

A Ford Model A offered enormous parts support and mechanical simplicity, but its standard engine was a four-cylinder. Chevrolet's 1929 six used overhead valves, contrasting with the Dodge's L-head layout. The DA countered with Dodge's established hydraulic-brake practice and a notably robust chassis, while retaining conventional side-valve maintenance.

Sport Roadster Versus DA Coupe and Sedan

Closed DA bodies provide greater weather protection and can be quieter, but they also carry more body structure and trim. The Sport Roadster offers a more exposed driving experience and stronger visual appeal for many collectors. Its top mechanism, rumble-seat structure, open-body alignment, and scarce trim can make a correct restoration substantially harder than restoring a complete sedan.

Ownership and Restoration Notes

The DA engine is understandable to a competent vintage-car machinist, but age and previous rebuilding matter more than the simplicity of the design. Check the block and cylinder head for freeze damage, cracks, corrosion around water passages, and evidence of excessive milling. Crankshaft condition, bearing clearances, camshaft wear, valve-seat recession, oil-pump condition, and connecting-rod alignment all require measurement rather than visual optimism.

Cooling systems accumulate scale and rust. A clean exterior on the radiator does not prove that its core flows correctly, and blocked block passages can produce localized overheating. The water pump, fan hub, belt alignment, and ignition timing should be addressed before fitting a modern auxiliary fan that masks the underlying fault.

Gearboxes commonly suffer from worn bearings, chipped teeth, damaged selector parts, and decades of operation with unsuitable lubricant. Rear axles need inspection for pinion-bearing wear, backlash, leaks, and axle-shaft condition. Brake restoration should include the complete hydraulic circuit rather than one visibly leaking cylinder.

Mechanical service parts can often be rebuilt or sourced through specialist suppliers and Dodge clubs. Sport Roadster body pieces are a different matter. Windshield hardware, top irons, rumble-seat fittings, deck components, garnish pieces, and correct instruments can take years to locate, making completeness more valuable than a freshly rebuilt but incorrectly assembled chassis.

Routine ownership requires frequent lubrication of chassis points, observation of coolant and oil levels, ignition-point adjustment, brake inspection, and periodic wheel-bearing service. Factory lubrication charts, not modern extended service intervals, should govern maintenance.

Buyer and Inspection Points

A DA Sport Roadster should be inspected as both a mechanical artifact and a piece of open coachwork. The table focuses on faults that can change restoration cost or undermine the identity claimed by the seller.

The best purchase is generally the most complete, well-documented body rather than the cheapest running chassis. Mechanical components can be remanufactured with specialist help, while missing roadster-only hardware may delay a project indefinitely.

Collector and Market Relevance

Open cars traditionally attract stronger collector attention than equivalent four-door sedans, but body authenticity determines whether that preference is justified. A genuine Sport Roadster retaining its original body, DA engine, instruments, top hardware, rumble-seat fittings, and period finishes has a different standing from a rebodied chassis, even when both are attractive touring cars.

Exact Sport Roadster production and survival totals are not consistently documented, so unsupported rarity claims deserve caution. Observable scarcity is nevertheless real: fewer open bodies survived weather, commercial reuse, wartime scrap drives, and incomplete prewar restorations than the more numerous closed cars.

Auction buyers tend to reward documentation, correct proportions, restrained paintwork, proper chassis detailing, and reliable operation. Excessive chrome, modern upholstery, incorrect wheels, hidden twelve-volt conversions, and non-period instruments can reduce historical credibility even when the work is expensive.

Cultural Relevance and Club Use

The DA Sport Roadster is not closely associated with a major factory racing program. Its modern visibility comes instead from antique-car tours, Dodge Brothers club activity, concours preservation, marque meets, and collections devoted to early Chrysler Corporation products.

The car also illustrates the American industry's rapid shift toward six-cylinder engines immediately before the Depression. Its engineering sits between the sparse simplicity of the Model A Ford and the larger, more elaborate multi-cylinder cars sold farther up the price scale. Surviving roadsters give that history a particularly clear shape because their open coachwork exposes the controls, chassis movement, and mechanical sound that enclosed bodies partly isolate.

Period accessories and later speed equipment occasionally appear on restored cars, but there was no widely recognized factory-backed DA tuning culture comparable with later Dodge performance programs. For historical presentation, carefully researched factory equipment usually carries more weight than speculative hot-rodding.

Frequently Asked Questions

What engine is fitted to the 1929–1930 Dodge Brothers DA Six Sport Roadster?

It uses a naturally aspirated 208-cubic-inch L-head inline-six. Period specifications commonly rate the engine at 63 horsepower, driving the rear wheels through a three-speed manual transmission.

What does the DA designation mean on an early Dodge?

DA is the Dodge series designation for this model family, not a modern trim acronym. It identifies the chassis and mechanical series and distinguishes the car from the Standard Six, Victory Six, Senior Six, and subsequent Dodge lines.

How can a genuine DA Sport Roadster be identified?

Confirm the DA serial evidence first, then inspect the cowl, doors, windshield supports, rear deck, rumble-seat structure, floor, and inner seams for consistent factory construction. Engine, body, title, and serial evidence should agree chronologically, although early cars do not necessarily use one identical number on every assembly.

Did the DA Sport Roadster have a special high-output engine?

No separate factory high-performance Sport Roadster engine is documented. The Sport Roadster designation refers to its open body and passenger arrangement rather than a different compression ratio, carburetor, camshaft, or competition package.

What are the most common restoration problems?

Typical concerns include cracked or scaled engine blocks, restricted radiators, worn steering joints, deteriorated hydraulic brakes, damaged transmission gears, frame repairs, and missing roadster-specific hardware. The top irons, windshield fittings, rumble-seat parts, and correct instruments may be harder to source than routine engine service components.

Are parts available for a Dodge DA Six?

Many ignition, bearing, brake, gasket, and engine-rebuilding needs can be addressed by vintage-parts specialists, remanufacturers, and Dodge clubs. Original Sport Roadster body hardware is much scarcer, so purchasing a complete car usually saves substantial time and fabrication expense.

What makes the DA Sport Roadster collectible?

Collectors value the combination of the 208-cubic-inch six, four-wheel hydraulic brakes, early Chrysler-era Dodge history, open coachwork, and rumble seat. Original body construction, documented identity, complete hardware, and conservative restoration quality matter more than unsupported claims about production rarity.

Collector Takeaway

The DA Sport Roadster matters because it records a precise change in American motoring. In 1929, Dodge could sell a mainstream open car with six-cylinder power, hydraulic brakes, and a 112-inch chassis while preserving the upright radiator, separate fenders, running boards, and rumble seat of the late 1920s. Within a few years, enclosed bodies and more integrated styling would make that formula look markedly older.

A correct example should be judged from the inside out: authentic DA identification, an original or convincingly documented roadster body, complete open-car hardware, sound hydraulic brakes, and a properly rebuilt long-stroke six. Fresh paint cannot replace those qualities. When they are present, the car offers something a sedan cannot reproduce, namely the full mechanical texture of an early Dodge chassis combined with one of the DA family's cleanest and least frequently surviving bodies.