Quick Facts

The core specifications establish what belongs to the DP series and separate it from nearby Dodge models that may look similar after decades of modification.

DP is the Dodge series designation, not a modern chassis number in the postwar European sense. Exact body-style production totals are not consistently documented across surviving references, so broad production claims for the Convertible Coupe should be treated cautiously unless supported by factory records.

Why the Dodge DP Convertible Coupe Matters

The DP made hydraulic four-wheel braking, six-cylinder power, and Chrysler Corporation's rubber-isolated Floating Power mounting system available in a Dodge priced against cars such as the Chevrolet Master Eagle and Ford's Model 40. Ford advertised the appeal of its 221-cubic-inch V8, while Chevrolet continued to develop its overhead-valve six. Dodge answered with a conservative side-valve engine and a chassis whose braking and isolation were central selling points.

The Convertible Coupe matters because open bodies had low survival rates and are expensive to reconstruct correctly. The folding roof, header, rumble-seat structure, drainage paths, door fit, and model-specific brightwork all introduce problems absent from a closed DP sedan. A genuine, substantially complete Convertible Coupe therefore tells far more than a rebodied chassis or an incomplete restoration assembled from unrelated Dodge parts.

Historical Context and Development

By the 1933 model year, Dodge had been under Chrysler Corporation ownership for several years. The brand shared the corporation's emphasis on hydraulic brakes, conventional six-cylinder engines, and coordinated engineering, but retained Dodge-specific dimensions, styling details, and series identities. The DP sat above Plymouth in the corporation's hierarchy and below Chrysler-branded offerings, although equipment and retail pricing depended on body style and accessories.

The Depression sharply compressed the new-car market. Buyers compared fuel cost, durability, purchase price, and dealer support with unusual care, and manufacturers revised products rapidly in response. Dodge's DP competed directly with Chevrolet's six-cylinder Master Eagle and Ford's V8-powered Model 40, two formidable alternatives with very different engineering arguments.

The 1933 Dodge adopted the period's move away from the upright, rectilinear forms of the late 1920s. Its grille leaned rearward, the hood and cowl formed a more continuous profile, and the separate fenders acquired deeper, more flowing crowns. On the Convertible Coupe, the low folded roof and compact passenger compartment emphasized the long hood, while the rumble-seat deck and rear-mounted spare gave the tail visual weight.

The DP was not a homologation model, and Dodge did not develop the Convertible Coupe around a formal competition program. Its significance comes from series-production road engineering and body-style rarity, not from an invented racing pedigree.

Engine and Drivetrain

The DP's engine was a water-cooled, inline six with its valves located in the block beside the cylinders, the arrangement commonly called an L-head or flathead. A 3.125-inch bore and 4.375-inch stroke produced 201.3 cubic inches. Factory specifications commonly list 70 brake horsepower at 3,600 rpm.

A single downdraft carburetor supplied the naturally aspirated engine. Battery-and-coil ignition fired six spark plugs through a distributor, while a mechanically driven water pump circulated coolant through the block, cylinder head, and radiator. Pressure lubrication served the engine's principal bearings, although any rebuild should follow the original oiling layout rather than assumptions based on later full-flow filtration systems.

Dodge's Floating Power system used rubber mountings intended to keep engine vibration out of the frame and body. The six drove through a dry single-plate clutch and three-speed manual gearbox to a propeller shaft and live rear axle. Neither overdrive nor an automatic transmission formed part of the standard DP Convertible Coupe specification.

The documented dimensions below are the useful baseline for assessing an engine offered as correct for a DP.

Compression-ratio and carburetor-detail listings are not fully consistent among abbreviated modern references. For restoration, a factory shop manual, period parts book, and the physical casting and stamping evidence are safer than a generalized online specification.

Chassis, Suspension, and Braking

The DP used separate body-and-frame construction on a 111.25-inch wheelbase. Its front suspension retained a beam axle on semi-elliptic leaf springs, while the live rear axle also used semi-elliptic springs. Hydraulic shock absorbers controlled spring motion, and the long wheelbase favored stability over quick directional response.

Four-wheel internal-expanding hydraulic drum brakes were a meaningful Dodge feature when mechanical brake linkages remained common in the market. The system eliminated rods and cables as the primary means of applying the shoes, but it still required careful adjustment, round drums, sound wheel cylinders, and uncontaminated linings.

Period cars are commonly seen on 17-inch wheels with narrow cross-ply tires. Wheel type, hubcap design, finish, and tire size should be checked against Dodge literature for the exact car because later wheels can fit while materially changing appearance and steering effort.

This table concentrates on hardware that affects both authenticity and road behavior.

The beam axle and tall tire sidewalls allow substantial unsprung movement on rough roads, while the leaf springs also locate the axles. Worn shackles, dry spring leaves, loose steering joints, or ineffective dampers can make a sound basic design feel far less controlled than Dodge intended.

Driving Experience and Road Manners

A properly rebuilt DP Six should start with a measured, even idle rather than a modern engine's near-silent smoothness. The long-stroke six develops its useful response at modest engine speed, and the heavy flywheel helps the car pull away without drama. Acceleration is deliberate, particularly with passengers or on a gradient, but flexible low-speed delivery suits the three-speed gearbox.

The gear lever requires an unhurried hand. Synchromesh provision and shift practice differ from a modern transmission, so forcing a cold gearbox invites gear clash and wear. Double-declutching on downshifts is sympathetic technique even where the transmission permits a less formal approach.

At parking speed the steering is heavy, especially if the tires are underinflated or wider than standard. It becomes lighter once moving, with slower response and more correction than a later independent-front-suspension car. The narrow tires and compliant springs communicate surface changes clearly, while the open body may reveal cowl shake or door movement that a closed sedan conceals.

Good hydraulic drums provide progressive stopping on period roads, but they lack the heat capacity, water resistance, and repeated high-speed consistency expected from modern brakes. A low pedal or pull to one side is a fault, not an inherent period characteristic.

Identification and Originality

Serial, Engine, and Body Evidence

A 1933 Dodge predates the standardized 17-character VIN. Identification rests on the factory serial-number plate, the DP series designation, the engine stamping, body-number evidence, and supporting paperwork. The engine number and vehicle serial number were separate factory sequences, so matching numbers should not be interpreted as two identical stampings.

Inspect the serial plate itself, its attachment, typeface, and surrounding metal. A fresh plate on an old body, disturbed fasteners, or a number unsupported by registration history deserves investigation. The engine stamping should be examined for the correct DP-related prefix and an undisturbed pad, then checked against period Dodge serial and engine-number references rather than decoded from memory.

Body tags and numbers can help establish coachwork identity, but they should be treated as part of an evidence chain. A frame, engine, cowl, doors, rumble-seat opening, top mounting points, and rear body structure must agree with the claimed Convertible Coupe configuration. A title describing a coupe does not prove that an open body is factory-original.

Correct Equipment and Finishes

High-value details include the grille shell and insert, hood panels and louvers, lamps, handles, windshield frame, top irons, header hardware, rumble-seat hinges and steps, dashboard instruments, steering wheel, wheel covers, and exterior moldings. Closed-car trim can look nearly right while differing in section, length, or mounting location. Later Dodge engines are another common substitution because related flathead sixes remained available for decades.

Dodge did not use the later-style option sticker or modern RPO system familiar to postwar collectors. Sidemount equipment, luggage racks, heaters, radios, wheel treatments, and other accessories should be supported by period catalogs, installation evidence, or factory documentation where available. Date-coded electrical components can aid research, but service replacements are normal and should be disclosed rather than restamped.

Paint should be matched to period Dodge color literature and surviving protected samples, not simply to a modern color carrying a period-sounding name. Convertible upholstery, top material, binding, floor covering, and rumble-seat trim require the same discipline. Excessively glossy paint, modern vinyl, exposed Phillips-head screws, and polished hardware where plated or painted parts belonged can undermine an otherwise expensive restoration.

DP Six Body and Trim Variants

The DP series was sold in several body forms sharing the same basic six-cylinder mechanical package. Surviving sales catalogs and references differ in how certain coupe and sedan descriptions are grouped, so body-number and construction evidence remain essential.

No factory homologation, competition, or high-output Convertible Coupe derivative is associated with the DP series. Exact production by body style is not consistently documented in readily available records, and estimates should not be substituted for a factory body count.

Performance and Dimensional Specifications

Reliable factory dimensions are more readily established than acceleration figures. Period road tests did not document the DP Convertible Coupe with the consistency later applied to postwar cars, and credible model-specific 0-to-60 mph, quarter-mile, and maximum-speed figures should not be inferred from other body styles.

Published weights can differ according to body description, equipment, and whether a source reports shipping or road-ready weight. The same caution applies to top speed, which changes with axle ratio, tire diameter, engine condition, weather, and test method.

Compared With Related Dodge and Contemporary Models

Dodge DP Versus the Earlier Dodge Six

The DP's styling is a primary separator from late 1920s and early 1930s Dodge models. Its more inclined radiator treatment and integrated hood-to-cowl line look noticeably more modern than the upright bodies that preceded it. Mechanical parts may resemble adjacent Dodge sixes, but displacement, mounting details, controls, and body hardware must be checked by series rather than assumed interchangeable.

Dodge DP Versus Plymouth

Plymouth served the lower-priced end of Chrysler Corporation's range and used its own series codes, dimensions, engines, trim, and body details. Similar corporate engineering does not make a Plymouth chassis or body a DP. Converted cars are best detected by checking serial evidence, frame dimensions, dashboard stampings, body construction, and the fit of front sheet metal.

Dodge DP Versus Ford Model 40 and Chevrolet Master Eagle

Ford's 1933 Model 40 offered the marketing and performance appeal of the flathead V8, although four-cylinder Fords were also sold. Chevrolet's Master Eagle relied on an overhead-valve inline six. Dodge countered with an L-head six, hydraulic brakes, and Floating Power mountings, giving buyers three distinct engineering choices in the same market.

Dodge DP Versus Later Dodge Sixes

Later Dodge flathead six-cylinder engines can be made to fit early chassis, which explains why many surviving prewar cars no longer retain their original engine. A later replacement may improve serviceability, but it changes collector assessment and can introduce incorrect accessories, mounting arrangements, cylinder-head details, and stamping formats.

Ownership and Restoration Notes

The flathead six is fundamentally durable when its cooling and lubrication systems are clean. Long-stored engines often suffer from stuck valves, corroded water passages, deteriorated fuel-system components, and sludge in the sump. Before attempting to start one, inspect cylinder condition, oil flow, coolant passages, distributor operation, fuel lines, and the condition of the wiring harness.

Cooling-system restoration may require more than a recored radiator. Rust scale collects in the block, water-distribution passages deteriorate, and an apparently clean radiator cannot compensate for restricted internal circulation. Persistent overheating should be diagnosed systematically rather than hidden with an electric fan.

The gearbox, clutch linkage, propeller shaft, and rear axle are serviceable by an experienced prewar specialist, but hard parts are less casually available than tune-up components. Gear noise on overrun, jumping out of gear, excessive driveline lash, and oil contamination all justify closer inspection. Brake cylinders and lines should be rebuilt as a system after prolonged storage.

Body restoration is the decisive expense. Inspect the lower cowl, door bottoms, sills, floor edges, rear wheel housings, deck and rumble-seat gutters, spare-wheel mounting area, and every point where wood, fabric, and steel trap moisture. Open-car door alignment depends on the body structure, so braces should be installed before weakened sills or floors are cut away.

Mechanical service parts, ignition pieces, brake consumables, and some engine components can be sourced through vintage Chrysler specialists and clubs. Convertible-only garnish moldings, top irons, windshield hardware, rumble-seat fittings, and correctly profiled trim may require restoration of original pieces or skilled fabrication. Reproduction availability should never be assumed from the existence of parts for a Ford or Chevrolet of the same year.

Buyer and Inspection Points

A credible inspection begins with identity and body structure, not a warm engine or fresh paint. The following checks target the areas most likely to separate a sound DP Convertible Coupe from an expensive collection of unrelated parts.

Evaluate completeness before cosmetic quality. A weathered but intact car with its original top hardware, windshield assembly, dashboard, rumble-seat fittings, and trim may be a better restoration basis than a glossy example missing irreplaceable components.

Collector and Market Relevance

Collectors generally favor the Convertible Coupe over closed DP body styles because of its open body, rumble seat, stronger visual proportions, and lower survival rate. That preference does not erase differences in authenticity. A documented car retaining its correct body structure and major hardware normally carries more historical weight than a reconstructed example assembled around an available DP frame.

Restoration economics are demanding. Chrome work, top fabrication, wood replacement where required, instrument restoration, upholstery, body alignment, and missing trim can exceed the cost of rebuilding the flathead six. Consequently, finished cars are judged closely for panel fit, plating quality, top profile, paint authenticity, engine identity, and the use of correct fasteners and finishes.

Auction interest tends to concentrate on complete, properly identified open cars and older restorations that remain mechanically usable. Modified drivetrains, modern interiors, hydraulic conversions of uncertain workmanship, and incorrect wheels narrow the audience, even if they make the car easier to drive casually.

Cultural Relevance and Club Support

The DP Convertible Coupe reflects the American rumble-seat road car at the point when enclosed sedans were becoming the dominant practical choice. Its body combined weather protection sufficient for occasional use with the visual drama of a fully open roof and an exterior rear seat, a format that declined as integrated passenger compartments became standard.

The model has no defining factory racing campaign, and claims of competition provenance require car-specific documentation. Its modern visibility comes chiefly through preservation groups, concours events, touring clubs, and organizations devoted to Dodge Brothers and Chrysler Corporation vehicles. Club archives and owner networks are particularly valuable when locating patterns, original hardware, or cars from which missing details can be measured.

Unlike the 1933 Ford, the DP did not become a major postwar hot-rodding template. That reduced its aftermarket profile but helped some survivors escape extensive customization. When a modified DP appears, restoring the missing Dodge-specific pieces can be substantially harder than reversing equivalent changes on a Ford supported by a vast reproduction industry.

Frequently Asked Questions

What engine does the 1933 Dodge DP Six Convertible Coupe use?

It uses a naturally aspirated 201.3-cubic-inch L-head inline six with a 3.125-inch bore and 4.375-inch stroke. Factory specifications commonly rate it at 70 bhp at 3,600 rpm.

What does DP mean on a 1933 Dodge?

DP is Dodge's model-series designation for this 1933 Six. It should appear consistently in the car's serial and engine identification evidence, but it is not a modern 17-character VIN or a European-style platform code.

Did the Dodge DP Convertible Coupe have a rumble seat?

Yes. The Convertible Coupe configuration is identified with folding open coachwork and a rear rumble seat, including the associated deck opening, hinges, steps, drainage, and inner structure.

How can a genuine DP Convertible Coupe be identified?

Check the factory serial plate and title against DP references, examine the engine prefix and stamping, and verify that the cowl, doors, windshield mounting, top points, rumble-seat structure, and frame agree with a factory open car. No single tag should substitute for the complete physical and documentary record.

Are parts available for a 1933 Dodge DP Six?

Routine ignition, brake, engine, and service parts can often be sourced through prewar Chrysler specialists and clubs. Convertible-only top hardware, windshield parts, body trim, rumble-seat fittings, and correct interior pieces are much harder to find and may require restoration or fabrication.

What are the most serious restoration problems?

Weak sills and floors, deteriorated top structure, damaged rumble-seat gutters, missing open-car hardware, cooling-system corrosion, worn steering joints, and incomplete hydraulic brake repairs are the principal concerns. Structural body work and missing trim usually cost more to solve than ordinary engine servicing.

What makes the 1933 Dodge DP Convertible Coupe collectible?

Collectors value its scarce open body, rumble seat, 1933 styling, hydraulic brakes, Floating Power engine mounting, and correct 201.3-cubic-inch six. Authentic body construction, complete top hardware, original identification, and documented restoration work have greater significance than cosmetic shine alone.

Collector Takeaway

The 1933 Dodge DP Six Convertible Coupe deserves attention for specific reasons: it carries Dodge's 201.3-cubic-inch flathead six, hydraulic four-wheel brakes, Floating Power mountings, and a body whose rumble seat and folding roof sharply reduced practicality while greatly increasing restoration complexity. It also records Dodge's response to Ford's V8 and Chevrolet's overhead-valve six during one of the harshest years in the American motor industry.

Buy the body, hardware, and documentation first. The engine can be rebuilt, the brakes can be sleeved, and the springs can be reset, but an incorrect open body or a car stripped of its windshield, top irons, rumble-seat fittings, and DP trim is a far more difficult proposition. The best examples preserve the evidence that they left the factory as Convertible Coupes, which is precisely what makes this particular Dodge worth separating from the many sedans, reconstructed cars, and later-engine conversions that share its basic outline.