Quick Facts

The following summary separates the well-established DA specifications from figures that differ among surviving catalogs, registration records and later reference works.

The DA designation is a factory model-series code rather than a modern standardized chassis number. It identifies the mechanical family, while the individual serial number, engine number and any surviving body tag must be examined separately when authenticating a car.

Why the DA Convertible Coupe Matters

The Convertible Coupe offered weather protection that the DA roadster could not match. Its framed, winding side windows made it closer to a closed coupe with a removable roof than to a roadster with side curtains, while the rumble seat preserved occasional rear-passenger capacity. That distinction matters during identification because unfinished roadster projects have sometimes acquired improvised glass, tops or coupe components during later restorations.

Mechanically, the car represented Dodge's response to a market moving decisively toward six-cylinder engines. The side-valve design did not chase high engine speed, but its long 4.1875-inch stroke produced the low-speed flexibility expected of an American touring car. Four-wheel hydraulic brakes were another substantive sales point when several competitors still relied on mechanically actuated systems.

The Convertible Coupe also survives in much smaller numbers than DA sedans. Exact body-style production totals are not consistently documented in commonly available factory records, so unsupported rarity claims should be treated cautiously. Even without a defensible production figure, the low survival rate of open bodies is evident in club registers, restoration projects and the difficulty of finding original top and rumble-seat fittings.

Historical Context and Development

Dodge Brothers After the Chrysler Acquisition

Chrysler Corporation acquired Dodge Brothers in 1928, gaining a respected make, substantial manufacturing capacity and an established dealer organization. The transaction did not instantly erase Dodge engineering practice. The 1929 DA retained a separate ladder frame, a side-valve engine, solid axles and styling that remained recognizably related to late independent-era Dodge products.

Dodge had already marketed six-cylinder cars before the DA, including Standard, Victory and Senior series. The DA rationalized the bread-and-butter six-cylinder offering around a 112-inch-wheelbase chassis, while larger Dodge models served buyers seeking more space and displacement. Its engineering brief emphasized usable torque, hydraulic braking and conventional construction that dealers could service without unfamiliar equipment.

A Difficult Market at the End of the 1920s

The DA entered a market dominated by aggressive price competition. Ford's Model A used a 200.5-cubic-inch four, while Chevrolet's 1929 AC International introduced a 194-cubic-inch overhead-valve six to the low-priced field. Pontiac, Essex, Plymouth and other makes crowded nearby price classes, and body variety remained crucial because buyers expected one chassis family to support sedans, coupes and open cars.

The Wall Street crash occurred during the DA's run, and the contraction that followed reshaped the industry. Open bodies were especially vulnerable as closed cars became more affordable and practical. The Convertible Coupe consequently represents both a technical body style and the closing years of mainstream American rumble-seat motoring.

Design and Coachwork

The DA's appearance is governed by vertical forms: a tall radiator shell, upright windshield and narrow passenger compartment set behind a long louvered hood. Separate headlamps, exposed running boards and crowned fenders make the chassis visually legible in a way that disappeared as bodies became wider and more integrated during the 1930s.

With the top folded, the Convertible Coupe has a lower visual center than a DA sedan, but it is not a lightweight sporting body in the European sense. The substantial windshield frame, roll-up door glass and rumble-seat deck imposed more hardware than a roadster. Paint schemes, wheel finishes, pinstriping and plated details varied with catalog combinations and optional equipment, so restoration should begin with period color literature rather than a generic late-1920s palette.

There was no homologation requirement and no factory competition program that dictated the DA Convertible Coupe's specification. Dodge emphasized dependable road use, not racing eligibility. Any surviving car with speed equipment, altered manifolds or competition-style bodywork should be evaluated as a period modification or later custom unless documentation proves otherwise.

Engine and Drivetrain

The 208.4-Cubic-Inch Side-Valve Engine

The DA engine places its valves in the cylinder block beside the bores, the arrangement commonly described as L-head or flathead. A gear-driven camshaft operates the valves through mechanical tappets. The detachable cylinder head is comparatively simple, but corrosion, incorrect gasket installation and past resurfacing can still create cooling and compression problems.

A single downdraft or updraft carburetor arrangement, depending on documented production equipment and replacement history, supplies the engine through a cast intake manifold. Surviving cars frequently carry replacement carburetors, distributors and fuel-delivery components fitted during decades of use, making factory literature and date-appropriate component catalogs essential during judging-level restoration.

Ignition is by battery, coil and distributor in a six-volt electrical system. Cooling uses a belt-driven fan and water circulation through the block, head and radiator, while pressure lubrication serves the engine's principal bearings. Owners should not judge hot oil pressure or cooling performance by modern standards, but persistent bearing noise, water in the oil or localized boiling requires investigation.

The core published dimensions are consistent enough to provide a useful mechanical reference.

Published torque and maximum engine-speed figures are not sufficiently consistent to justify precise entries. What the bore-and-stroke dimensions establish is a notably undersquare engine, designed to work at modest crankshaft speed rather than reward sustained high-rpm operation.

Clutch, Gearbox and Rear Axle

A dry plate clutch connects the engine to a floor-shifted three-speed transmission. The gearbox predates synchromesh as modern drivers understand it, so clean changes require deliberate timing, a pause in neutral and, on downshifts, double-declutching. Gear oil that is too heavy can worsen cold shifting, while an incorrect modern lubricant may be unsuitable for period yellow-metal components.

The enclosed driveline sends power to a live rear axle. Differential noise under load or on overrun can point to worn bearings, poor gear contact or earlier assembly errors. Axle-ratio information should be confirmed from the individual assembly because replacement rear axles and gearsets are not unusual on cars that remained in service through the 1940s and 1950s.

Chassis, Suspension and Braking

The DA uses a conventional pressed-steel ladder frame with the engine mounted longitudinally at the front. Rigid front and rear axles are suspended by semi-elliptic leaf springs, an arrangement chosen for durability and load control rather than independent wheel movement. Lever or period hydraulic shock absorbers, where specified, must be identified against factory parts information because later tubular conversions are common.

Four-wheel hydraulic internal-expanding drum brakes were a notable Dodge feature. Their basic principle is familiar, but the small wheel cylinders, flexible hoses, master cylinder and drum condition demand careful rebuilding. Fluid contamination and long storage can seize cylinders even when the pedal initially feels firm.

This table concentrates on dimensions and equipment that materially affect restoration, wheel fit and chassis setup.

The rigid axles allow camber and steering geometry to remain simple, but worn kingpins, spring shackles and steering joints compound one another. A DA that wanders badly is not merely displaying old-car character. It is often signaling accumulated wear, incorrect toe setting, mismatched tires or a distorted axle.

Driving Experience and Handling Dynamics

A correctly adjusted DA starts with a measured rhythm. The long-stroke engine delivers its useful pull early, and the driver progresses through the unsynchronized transmission without hurrying the lever. Throttle response is softer than that of a later short-stroke engine, but the six should run evenly and pull from low road speed without persistent misfire or harsh mechanical knock.

Steering effort is substantial while parking, especially with underinflated tires, then eases once the car is moving. The tall wheel provides leverage, while the steering box and multiple linkage joints introduce more free movement than a modern rack. Correctly rebuilt components produce a progressive response, not the quarter-turn of slack sometimes dismissed as normal.

The leaf springs and narrow tires suit the speeds and uneven surfaces of the period. Body roll arrives early, and the high seating position magnifies it, but the car should settle rather than continue oscillating. The open body may show more cowl movement than a closed sedan, particularly if its body sills, wood reinforcement or mounting pads have deteriorated.

Hydraulic brakes give the DA a meaningful advantage over contemporary mechanical-brake cars when all four drums share the work evenly. They still require anticipation. Drum roundness, shoe arc, hose condition and wheel-cylinder adjustment determine whether the pedal produces a straight stop or an alarming pull.

Period acceleration, quarter-mile and verified maximum-speed figures for the Convertible Coupe are not consistently available. The dependable published dimensions and factory output are therefore more useful than optimistic modern estimates.

Body weight listings differ according to year, equipment and the conventions used by period publications. A claimed curb weight or top speed should be tied to a dated factory sheet or contemporary road test before being treated as definitive for the Convertible Coupe.

Identification and Originality

Serial, Engine and Body Numbers

A prospective buyer should first establish that the chassis serial falls within the documented DA sequence for the relevant model year. Early registrations often recorded an engine number instead of the chassis serial, and replacement engines can leave a car with a title that no longer corresponds to its principal identification plate. Plate location, typography and attachment method should be compared with authenticated DA examples and marque-club records rather than inferred from later Dodge practice.

The engine number is a separate identifier stamped on the block. Dodge did not use matching numbers in the later muscle-car sense, where every major component repeats a complete vehicle identification number. For a DA, originality means that serial chronology, engine type, casting characteristics and body details agree with the production period, supported where possible by an old title, registration, sales invoice or restoration photographs.

Any body number or supplier tag should be recorded before stripping paint. Such a tag may help confirm coachwork sequence, but it is not a substitute for the chassis serial. Reproduction data plates are available for many antique cars, so a fresh plate on an otherwise aged chassis demands documentary support.

Convertible Coupe Body Clues

The factory Convertible Coupe should have the structural provisions and hardware for framed roll-up side glass, a folding top and a rumble-seat deck. Door construction, windshield sealing, top-iron mounting points, interior quarter trim, seat framing and rear-deck drainage are more persuasive than a later registration that merely says convertible.

Roadsters and closed coupes can donate numerous visible pieces, but they do not automatically provide the correct convertible door structure or top geometry. A basket-case body assembled from mixed DA panels may look convincing until the doors, glass and top are installed. Poor gaps can originate in corroded sills or displaced body mounts rather than inaccurate outer sheet metal.

Correct Equipment and Finishes

Carburetors, distributors, generators, starters, horns, lamps and gauges were service items and are often replacements. Casting numbers and date evidence can help, but a component should not be condemned solely because it lacks a modern-style date code. The correct approach is to compare its manufacturer, model, mounting pattern and period application with Dodge parts books.

Factory option coding was not presented on a modern build sheet or fender tag. Sidemount spares, wheel type, trunk equipment, lamps and interior fittings must be checked against dated sales literature for the precise market and year. Period accessories can be historically appropriate without being factory-installed.

Original paint names and combinations should come from period Dodge color charts or surviving protected areas beneath hardware. Modern generic maroon, cream wheels and excessive pinstriping may produce a plausible late-1920s appearance while remaining incorrect for a particular car. Nickel or chromium treatment likewise needs component-by-component research because restorations often plate every bright part uniformly.

DA Six Body and Trim Breakdown

The DA family supported several body styles on the same basic mechanical platform. Catalog availability could differ by model year and market, and exact body-style production totals are not consistently documented, so the table avoids speculative quantities.

The Convertible Coupe and Sport Roadster should not be treated as interchangeable open bodies. The glass, doors, roof apparatus and associated timber or metal reinforcement create different restoration problems even when major chassis and front-sheet-metal parts appear similar.

Compared With Related Dodge Models

DA Versus the 1928 Victory and Standard Sixes

The late-1920s Dodge range used multiple six-cylinder series with overlapping body choices. A surviving car should not be identified as a DA merely because it has a Dodge six and similar upright styling. Wheelbase, serial evidence, engine dimensions, radiator shell, hood, cowl and body mounting points must agree.

The 1928 Victory Six also used a 208-cubic-inch-class engine, which creates particular confusion when loose engines and incomplete projects change hands. Shared displacement does not prove that every casting, accessory mounting point or external component is correct for a 1929 or 1930 DA.

DA Versus the Larger Senior Dodge

The Senior series offered a larger chassis and different engine specification for buyers requiring greater passenger room and prestige. Its body panels and brightwork can resemble DA pieces in photographs while differing enough to be unusable. Dimensions should be taken from the actual part before purchasing expensive sheet metal or radiator components.

DA Versus the 1930 DD and Later DH Six

Dodge's model progression accelerated under Chrysler. The 1930 DD used a different, shorter-wheelbase six-cylinder package, while the 1931 DH moved Dodge styling and engineering further into the Chrysler corporate pattern. Later engines and transmissions may be workable service substitutions, but they can change mounts, controls, driveline length and judging eligibility.

The DA therefore needs to be researched as its own series, not as a generic prewar Dodge. Mechanical interchange is often broader than body interchange, yet even apparently identical service parts may have year-specific shafts, flanges or control linkages.

Ownership and Restoration Notes

Engine and Cooling-System Work

A DA engine rebuild should begin with measurement, crack testing and inspection of the cooling passages. Long storage allows scale to collect around the rear cylinders, and a cosmetically restored radiator may still lack adequate internal flow. Cylinder-head studs, water-pump components and manifold fasteners require patient removal because broken hardware can turn a routine overhaul into major machine work.

Bearing clearances, crankshaft condition, connecting rods and oil-pump performance require a machinist familiar with prewar engines. Installing modern materials without accounting for original oil delivery, shaft finish and thermal expansion can shorten engine life. Valve seats and guides also deserve close examination, particularly if the car has been operated for years with poor mixture control or retarded ignition.

Fuel, Ignition and Electrical Systems

Old fuel tanks commonly contain corrosion, varnish and failed sealant. Rebuilding the carburetor without cleaning the tank and lines merely transfers debris into the restored unit. Ethanol-resistant soft parts can improve service reliability without advertising themselves visually.

Six-volt systems work properly when cable gauge, grounds, starter condition and charging output match the original design. Thin 12-volt-style battery cables produce slow cranking and encourage owners to convert the entire car unnecessarily. A discreetly maintained original-voltage system is preferable for a car being restored to factory configuration.

Body Structure and Trim

The Convertible Coupe body is usually the most expensive part of the restoration. Check structural wood or reinforcement around the door openings, windshield, top mounts, rear deck and body sills, together with the metal brackets that locate those pieces. A body can be painted beautifully and still be incapable of holding consistent door gaps once it is bolted to the chassis.

Top irons, latches, window regulators, glass channels, rumble-seat hinges and deck hardware are difficult to source. Reproduction rubber, wiring, bearings and general service parts are more obtainable than open-body trim. Missing castings may have to be borrowed as patterns and reproduced by a specialist, adding far more expense than their size suggests.

Service and Use

There is no sensible universal service interval for an antique car whose annual mileage, oil type and rebuild history are unknown. Before regular use, check engine oil, gearbox and axle lubricant, coolant, brake fluid condition, wheel-bearing adjustment, steering joints and chassis lubrication. Frequent attention to grease points and brake adjustment is part of operating the car, not evidence of a defect.

Buyer and Inspection Points

A DA Convertible Coupe should be purchased on completeness and structural integrity before cosmetics. The following checks target faults that can alter both restoration cost and the car's identity.

A running but incomplete Convertible Coupe may be a poorer proposition than a disassembled car retaining every original bracket and fitting. Mechanical systems can usually be rebuilt from patterns and standard processes. Missing open-body hardware often consumes more research, fabrication and test fitting than an engine overhaul.

Collector and Market Relevance

Collectors generally favor the Convertible Coupe over the DA sedans because fewer open cars survive and because the body delivers a stronger visual contrast between long hood, compact cabin and short rear deck. Desirability depends heavily on authenticity. A correct but gently aged car can be more informative than a highly finished restoration assembled from mixed roadster, coupe and later Dodge components.

Cars with continuous documentation, original serial plates, a period-correct engine and complete convertible hardware receive the closest attention. Factory color evidence, intact instruments and original upholstery patterns also matter because they provide templates for future conservation. An undocumented engine replacement is less damaging than a questionable body conversion, provided the replacement is of correct DA type and is disclosed.

Auction appearances are irregular, and differences in completeness make simple price comparisons unreliable. A finished car with accurately fitted top and glass cannot be compared directly with an older restoration whose doors sag or whose rumble-seat structure is incomplete. Restoration invoices may exceed market recovery, especially when extensive wood, plating and one-off casting work is required.

The model has no major factory racing legacy to inflate its standing. Its collector case rests instead on open-body scarcity, Dodge Brothers engineering, hydraulic brakes and its timing at the beginning of Chrysler ownership. That makes originality and historical documentation more valuable than performance modifications.

Cultural Relevance and Club Support

The DA belongs to the era of rumble seats, roadside touring and independent coachwork conventions, even though Dodge increasingly built standardized bodies at industrial scale. Convertible coupes expressed a brief solution to all-weather open motoring before integrated steel roofs, heaters and improving ventilation made closed cars the default choice.

Dodge Brothers and broader antique-automobile clubs provide the most useful technical network for these cars. Club rosters, judging guides, parts exchanges and access to unrestored examples can settle questions that generalized restoration manuals cannot. The value of that community becomes apparent when identifying a windshield latch, top pivot or body bracket absent from commercial catalogs.

Period aftermarket accessories included trunks, lamps, heaters and dress-up equipment, while later owners sometimes fitted replacement carburetors, sealed-beam conversions or newer engines to keep cars usable. Such changes form part of an individual car's history, but they should not be represented as factory DA specifications without contemporary evidence.

Frequently Asked Questions

What engine does the 1929–1930 Dodge Brothers DA Six Convertible Coupe use?

It uses a naturally aspirated 208.4-cubic-inch L-head inline six with a 3.25-inch bore and 4.1875-inch stroke. Period specifications commonly list 63 bhp at 3,000 rpm.

Was the Dodge DA Convertible Coupe built in both 1929 and 1930?

Yes. The DA series spans the 1929 and 1930 model years, although running changes, equipment and catalog availability should be checked against the serial chronology of an individual car.

Is the DA designation a chassis code?

DA is the factory model-series designation and is often used as a chassis-family reference. It is not an individual vehicle identification number. Authentication requires the unique serial, engine stamping, body evidence and supporting documentation.

How does the Convertible Coupe differ from the DA Sport Roadster?

The Convertible Coupe uses framed roll-up side glass and a more substantial folding-roof arrangement. The Sport Roadster uses roadster-type open-body weather protection. Doors, top mountings and structural details should therefore be examined before accepting an incomplete body as a Convertible Coupe.

What are the most serious restoration problems?

Deteriorated body sills or structural wood, missing top hardware, damaged rumble-seat fittings, blocked cooling passages and neglected hydraulic brakes create the largest problems. Engine work is specialized, but missing convertible-specific parts can be even harder to resolve.

Are mechanical parts available for a Dodge Brothers DA Six?

General service items such as bearings, seals, wiring materials, brake components and engine-rebuild supplies can often be sourced or adapted by antique-car specialists. Original carburetors, instruments, trim, top irons, regulators and body castings are much less predictable and may require rebuilding or reproduction from patterns.

What makes the DA Six Convertible Coupe collectible?

Its appeal comes from the scarce open body, the 208.4-cubic-inch six, four-wheel hydraulic brakes and its place among the first Dodge models sold after Chrysler's 1928 acquisition. Collectors place particular weight on body authenticity, complete convertible fittings and credible serial documentation.

Collector Takeaway

The DA Convertible Coupe is worth preserving because it records a precise change in American motoring. Dodge combined a long-stroke side-valve six, hydraulic brakes and a traditional separate-frame chassis with an open body that offered real glass and better weather protection than a roadster. Within a few years, inexpensive closed cars would make that formula commercially marginal.

Buy the body, hardware and documentation first. A worn DA engine can be machined, a brake system can be sleeved, and a radiator can be recored. A missing set of correct top irons, fabricated convertible doors or an undocumented roadster conversion can absorb years of effort without ever producing an authentic car. The best DA Convertible Coupes are not merely the brightest restorations, but the examples that still explain exactly how Dodge Brothers built an all-weather open car at the end of the 1920s.