Quick Facts

The essential distinctions are the annual suffixes, the wheelbase reduction after 1931 and the increase in advertised engine output. The table concerns the Convertible Coupe specifically while identifying the wider model family to which it belongs.

The letter suffix is indispensable when comparing parts, literature or prospective purchases. A seller's broad description of a car as a “1931–1933 Series 345” does not resolve differences in chassis length, engine rating, body details or annual trim.

Why the Series 345 Convertible Coupe Matters

The Series 345 was built while Cadillac was trying to retain luxury buyers in a market damaged by collapsing incomes and shrinking automobile sales. LaSalle offered Cadillac engineering and dealer support at prices below comparable Cadillacs, but its role became harder to sustain as Buick improved and Cadillac introduced less expensive models of its own.

The Convertible Coupe gives that commercial story a particularly clear mechanical form. It retained a large, slow-revving V8, a separate frame, beam front axle and mechanical brakes while packaging them beneath sporting open coachwork. It was not a racing derivative or homologation model, and its significance does not depend on competition results. Its value lies in the combination of a short open body, Cadillac-developed running gear and very low Depression-era demand.

The 1933 Series 345-C also closes a distinct engineering chapter. For 1934, LaSalle adopted a new, more streamlined shape and a smaller straight-eight derived from Oldsmobile practice. The visual and mechanical break was substantial, making the 1931–1933 V8 cars a coherent group rather than minor variations of the later LaSalle.

Historical Context and Development

LaSalle as Cadillac's Companion Marque

General Motors introduced LaSalle for 1927 as a companion marque administered by Cadillac. The first LaSalle was also among the earliest production cars shaped under Harley Earl's direction, an achievement that helped persuade GM to establish its Art and Colour Section. Earl's early LaSalle work drew from contemporary European themes, particularly the low, close-coupled proportions associated with Hispano-Suiza.

By 1931, the marque had matured into a range of substantial V8 automobiles rather than a styling experiment. Cadillac supplied the engineering culture, production discipline and dealer network, while LaSalle maintained its own grille identity, badging and model designations. The Series 345 name should not be read as an exact statement of displacement, since the engine displaced approximately 353 cubic inches.

Depression-Era Conditions

The 1931 model arrived after the 1929 stock-market crash had begun to reshape the American luxury-car business. Packard, Lincoln, Pierce-Arrow, Chrysler Imperial and Cadillac all faced a rapidly contracting pool of customers. Packard's lower-priced Light Eight appeared for 1932, illustrating how aggressively established luxury manufacturers pursued buyers below their traditional price classes.

LaSalle production fell sharply during this period, and open two-door bodies naturally sold in smaller numbers than sedans. Exact Convertible Coupe totals are not consistently presented across surviving production references, so a defensible year-by-year body count should not be inferred from total LaSalle output.

Design Direction

The Convertible Coupe used the visual vocabulary of an early 1930s American prestige car: a tall radiator shell, long hood, separate headlamps, sweeping front fenders, running boards and a compact passenger compartment set well behind the front axle. The upright windshield and folding fabric top preserved the formal stance of the closed cars while reducing visual mass around the rear body.

Wire wheels and side-mounted spare wheels strongly affect the appearance of surviving examples, but equipment must be checked against the individual car's documentation. Dual side-mounts, trunk arrangements, wheel covers and accessory lamps are frequently added during restoration because they create a more elaborate presentation, not because every Convertible Coupe left the factory that way.

Engine and Drivetrain

The Series 345 engine was a 90-degree V8 with side valves, detachable cylinder heads and a displacement of 353 cubic inches. Its 3.375-inch bore and 4.9375-inch stroke produced a distinctly long-stroke layout, designed to deliver useful low-speed torque without high crankshaft speed.

A single carburetor supplied the engine, with period installations commonly associated with Detroit Lubricator equipment. Because carburetors, manifolds and linkages were often replaced during decades of service, an identification judgment should rely on the precise model-year parts book rather than the mere presence of a period-looking updraft unit.

Coil-and-distributor ignition, a belt-driven fan, pump-assisted water circulation and pressure-fed lubrication followed established Cadillac practice. The cooling system's capacity mattered in a large L-head engine because exhaust heat passed through the block around the valve chambers. Internal scale, blocked passages and a deteriorated radiator can therefore make an otherwise sound engine run hot.

A single dry-plate clutch fed a three-speed manual gearbox. Cadillac's synchromesh development made shifting less laborious than in many earlier nonsynchronized luxury cars, although the driver still benefits from deliberate movements and a pause through neutral. Drive then passed through an enclosed propeller shaft to a live rear axle.

These are the specifications that can be applied consistently across the three years without forcing undocumented torque or engine-speed figures into the record.

The output increase did not turn the LaSalle into a high-revving sporting car. It improved flexibility in a heavy chassis, particularly when pulling away in the higher ratios or climbing grades. Factory literature did not publish the standardized net horsepower, torque curves or electronic redlines expected for later automobiles, so modern comparisons require caution.

Chassis, Suspension and Braking

The Series 345 used separate body-and-frame construction. The body incorporated steel panels with substantial structural wood, particularly around the doors, roof and rear body. Wood deterioration can loosen hinges and panel joints even where exterior paint still appears sound.

A rigid front axle located by semi-elliptic leaf springs was paired with a live rear axle and longitudinal leaf springs. Lever-type hydraulic dampers controlled spring motion. The arrangement was durable and familiar to mechanics of the period, but it transmitted wheel movement and road camber more directly than the independent front suspensions that spread through the luxury market later in the decade.

Steering was by a manual steering box without power assistance. Large-diameter wheels reduced steering effort once moving, while the tall tires contributed compliance that the leaf springs alone could not provide.

Four-wheel mechanical drum brakes were standard. They require accurate adjustment of rods, levers, return springs and shoe clearances if all four wheels are to contribute evenly. A car with badly balanced brakes may pull sharply even though every drum and lining appears serviceable.

The principal chassis specifications also show how much Cadillac altered the package after the first model year.

The four-inch wheelbase reduction for 1932 and 1933 is not a minor catalog detail. It changes body mounting, frame dimensions, propeller-shaft requirements and the visual relationship between hood, cabin and rear axle. Parts advertised simply as fitting “Series 345” should therefore be treated skeptically until checked against year-specific dimensions.

Driving Experience and Road Behavior

A properly rebuilt 353 V8 starts with a subdued mechanical pulse and delivers its best work at modest engine speed. Throttle response is progressive rather than abrupt, with the long stroke and heavy rotating assembly favoring steady acceleration. The driver uses torque and early upshifts instead of chasing engine speed.

The clutch is substantial, and the long gear lever demands a measured hand. Synchromesh eases the move between forward ratios, but worn synchronizers, old lubricant or maladjusted linkage can produce baulking that should not be dismissed as normal prewar behavior. First gear is primarily for starting, while the upper ratios suit the broad torque curve.

At parking speed the steering is heavy, especially with underinflated tires or excessive caster. Effort falls once under way, and the long wheelbase gives the car strong directional stability. Steering precision depends heavily on kingpins, tie-rod ends, wheel bearings and the steering box, all of which can accumulate enough wear to create vague response.

The narrow tires and tall sidewalls move gradually toward their limits. Body roll is evident, but healthy dampers keep it from developing into repeated wallow. Broken leaves, seized shackles or ineffective dampers can transform that controlled motion into pitching and axle tramp.

Mechanical brakes provide usable stopping power when correctly set up, but their pedal feel and required anticipation differ markedly from hydraulic systems. The driver must leave distance, apply pressure progressively and account for wet linings. A well-adjusted car should stop straight; persistent pulling points to a fault, not an inherent personality trait.

Identification and Originality

Series, Chassis and Body Records

The first task is confirming that a claimed Convertible Coupe is a genuine 345-A, 345-B or 345-C rather than a rebodied chassis or a collection of components from several years. The annual series designation should agree with the frame, engine, body construction and year-specific trim. Cadillac-LaSalle Club references, factory parts books and surviving build documentation are safer guides than generalized online serial-number charts.

Early Cadillac and LaSalle identification practice often tied the engine number closely to the vehicle's identity, but stamping locations and number sequences must be checked against authoritative records for the exact year. The body plate and body number identify coachwork and production information; they should not be mistaken for the vehicle serial number.

Rebodying was not unusual when open-car values rose and usable sedan chassis remained available. Inspect body mounts, frame holes, rear crossmembers, rumble-seat structure and the fit between cowl and chassis for signs of fabrication. A beautifully restored open body is not proof that the car began life as a Convertible Coupe.

Matching Numbers and Date-Coded Components

“Matching numbers” has a different evidentiary burden on a 1930s LaSalle than on a postwar muscle car with standardized tags and stamped driveline derivatives. A persuasive claim requires a period-correct engine number in the expected sequence, consistent frame identification, the correct body plate and documentary continuity. An unstamped replacement block or freshly restamped number should be disclosed.

Carburetor, generator, starter, distributor and instrument dates can support a car's chronology, but not every component uses a convenient modern-style date code. Castings and supplier tags should be judged with model-specific literature. A component merely bearing a familiar Cadillac supplier name is not automatically correct for all three Series 345 years.

Correct Equipment and Finishes

Correct radiator shells, hood panels, lamps, bumpers, instruments, steering wheels, door hardware and wire wheels can be difficult to source. Restorers have also installed later hydraulic brakes, modern transmissions, alternators and replacement carburetors to improve road usability. Such modifications may be reversible, but they materially affect originality and concours eligibility.

Factory colors and upholstery combinations should be established through year-specific paint charts, sales literature, build records and protected remnants of the original finish. A modern color chosen because it appears “period” is not evidence of factory correctness. Look behind trim, beneath body hardware and inside enclosed panels for surviving paint layers before stripping begins.

Variant and Trim Breakdown

There was no factory homologation or competition version of the Series 345 Convertible Coupe. The meaningful variants are the three annual series, each tied to a distinct model year and, after 1931, a shorter wheelbase and higher advertised output.

Accessories do not create separate factory variants. Dual side-mounted spares, luggage racks, additional lamps and later wheel treatments should be documented individually rather than used to invent a special trim designation.

Performance and Dimensional Specifications

Uniform instrumented acceleration, quarter-mile and top-speed results are not reliably documented for every Series 345 Convertible Coupe year. Body weight, axle ratio, tire size and test method could materially alter a period result, so modern-looking precision would be misleading. The dependable dimensional comparison is the factory wheelbase, while output is the contemporary advertised rating.

Claims for a precise top speed or 0–60 mph time should be accompanied by a named period test and the tested car's axle ratio and body style. Sedan figures cannot be transferred automatically to an open two-door body, and restored engines may differ significantly in compression, carburetion and state of tune.

Compared With Related LaSalle and Cadillac Models

Series 340 Predecessor

The 1930 LaSalle Series 340 preceded the 345-A and belongs to an earlier annual designation. Although visually related and still part of LaSalle's V8 period, its chassis, trim and parts references should not be treated as interchangeable with the three Series 345 years.

Contemporary Cadillac V8 Models

Cadillac's contemporary V8 cars shared engineering principles and, in some cases, closely related mechanical components with LaSalle. They were nevertheless sold under separate model designations with different bodies, dimensions, trim and pricing. A Cadillac radiator shell, instrument or lamp may look plausible on a LaSalle while remaining incorrect for the chassis under examination.

The 1934 LaSalle Redesign

The most consequential comparison is with the 1934 LaSalle. That car abandoned the 353-cubic-inch Cadillac-derived V8 for a smaller straight-eight and adopted a lower, more streamlined body with a markedly different visual character. It should not be grouped mechanically with the 345-A, 345-B or 345-C.

The 1934 change also affects parts searches. Advertisements that describe a component as fitting “early LaSalle” may span cars with unrelated engines, frames and front-end hardware. Exact year, series and casting or part number matter.

Ownership and Restoration Notes

Engine and Cooling System

A complete 353 V8 rebuild belongs with a specialist familiar with early Cadillac architecture. Cylinder-block condition, valve-chamber corrosion, crankshaft wear, oil passages and the availability of correctly sized internal parts should be established before cosmetic work consumes the budget. Machining errors are expensive to reverse, and missing external hardware can be nearly as troublesome as worn internals.

Cooling problems often begin with accumulated scale, a restricted radiator, worn water-pump components or incorrect ignition and carburetor settings. Before condemning the basic engine design, verify coolant circulation, fan condition, timing and mixture. Repeated overheating can damage heads, gaskets and valve areas.

Gearbox, Axles and Brakes

Transmission noise on overrun, weak synchromesh and lubricant leaks deserve investigation. Replacement gears and shafts are not routine catalog purchases, so preserving serviceable original components matters. The clutch linkage, universal joints and rear axle must also be assessed as a connected driveline rather than isolated units.

Mechanical brakes reward exact assembly. Oval drums, contaminated linings, worn clevises and mismatched lever geometry can defeat careful adjustment. A hydraulic conversion may make a car easier for an unfamiliar shop to service, but it reduces mechanical authenticity and can conceal irreversible alterations to backing plates or the frame.

Body Structure and Trim

Structural wood is one of the largest restoration-cost variables. Doors that drop when opened, uneven cowl gaps, cracked paint at joints and a rumble-seat opening that no longer fits squarely all suggest movement beneath the skin. Replacing wood correctly often requires much of the body to be disassembled and braced.

Rust commonly develops in lower cowl sections, door bottoms, running-board mounts, floor edges, rear body corners and the rumble-seat well. The frame requires close inspection around spring hangers, crossmembers, body mounts and areas where mud remains trapped.

Reproduction support is selective rather than comprehensive. Routine ignition pieces, bearings, seals and brake lining can often be sourced or adapted by knowledgeable specialists, while model-specific castings, trim, instruments and body hardware may require repair, fabrication or years of searching. Buying a complete car is usually less costly than replacing a long list of absent brightwork.

Service and Documentation

Routine use should include frequent attention to chassis lubrication points, oil level, coolant level, brake adjustment, tire pressure and spoke condition. Service intervals in period manuals assume contemporary lubricants and regular mechanic attention, so the factory manual remains essential even if modern oils and greases are used.

Build records, old registrations, restoration photographs, correspondence and invoices add more than narrative interest. They can establish when an engine was changed, whether the body was transferred and which trim was present before restoration. On a rare open car, that evidence directly affects collector confidence.

Buyer and Inspection Points

A serious inspection should begin with identity and structure before proceeding to paint quality or engine sound. The following areas account for many of the largest financial and historical risks.

A pre-purchase drive should be long enough to reach full coolant temperature and include braking from moderate speed. Cold oil can temporarily conceal bearing noise and gearbox wear, while a brief idle test reveals little about cooling capacity.

Collector and Market Relevance

Open LaSalles generally attract stronger collector attention than equivalent sedans because fewer were built, fewer survived and the body exposes the long hood and rearward cabin proportions more clearly. Within the Series 345 group, provenance, correct body identity and completeness matter at least as much as model year.

The 345-C benefits from being the last LaSalle powered by the large 353 V8, while the 345-A retains the longer 134-inch chassis. Those differences create distinct preferences rather than a universal hierarchy. A documented, unrestored or accurately restored example of any year is more persuasive than a heavily accessorized car with uncertain origins.

Cars restored to high standards appear at major concours and specialist auctions, but paint gloss alone does not establish quality. Judges and informed buyers examine body authenticity, engine identity, factory-correct hardware, mechanical function and period-appropriate materials. Hydraulic brake conversions, modern drivetrains and invented color schemes can limit appeal among preservation-minded collectors even when they improve touring convenience.

LaSalles of this period are recognized within established prewar club culture, including the Cadillac & LaSalle Club and Classic Car Club of America community. Specialist knowledge, judging records and archival material available through these circles can be more valuable than generic price guides.

Cultural Relevance

The Series 345 was not developed for organized racing, and there was no homologation requirement behind the Convertible Coupe. Its cultural role came through styling, luxury motoring and the visibility of LaSalle as Cadillac's companion marque. The name also became embedded in American popular memory well beyond the original production run.

For automotive historians, the car documents the period after Harley Earl's early LaSalle success but before GM's mid-1930s embrace of streamlined bodies and independent front suspension. It shows how rapidly exterior fashion was changing while the underlying chassis still followed late-1920s practice.

Club tours and concours events remain natural settings for the model because correct examples demand both visual and mechanical scholarship. The strongest restorations preserve the contrast that defines the car: glamorous open coachwork above a conservative, durable Cadillac-developed chassis.

Frequently Asked Questions

What engine does the 1931–1933 LaSalle Series 345 use?

It uses a naturally aspirated 353-cubic-inch, approximately 5.8-liter, L-head V8. The engine has a 3.375-inch bore, a 4.9375-inch stroke and side valves.

How much horsepower does a LaSalle Series 345 Convertible Coupe have?

The 1931 Series 345-A is rated at 95 bhp. Period specifications commonly list 115 bhp for the 1932 345-B and 1933 345-C.

What is the difference between 345-A, 345-B and 345-C?

The suffixes identify model years: 345-A is 1931, 345-B is 1932 and 345-C is 1933. The 1931 car uses a 134-inch wheelbase, while the 1932 and 1933 cars use a 130-inch wheelbase and carry the higher advertised engine rating.

How can a genuine Series 345 Convertible Coupe be identified?

Identification requires agreement among the engine and frame numbers, body plate, annual series details, body mounting and period documentation. Because open bodies can be recreated on sedan chassis, the structure and provenance should be examined by a specialist familiar with prewar Cadillac and LaSalle records.

Does matching numbers matter on a prewar LaSalle?

Yes, but the evidence differs from that used for many postwar cars. A credible claim should be supported by the correct engine-number sequence, frame identification, body information and historical records rather than by a single plate or an unsupported seller statement.

What are the major restoration problems?

The principal cost risks are deteriorated structural wood, rust in lower body sections, an incomplete or incorrect 353 V8, cooling-system corrosion, worn mechanical-brake linkage and missing model-specific trim. Gearbox internals, instruments, lamps and open-body hardware can require specialist rebuilding or fabrication.

Are parts available for the LaSalle Series 345?

Service components can often be sourced through Cadillac-LaSalle specialists, established suppliers or careful adaptation. Series-specific castings, brightwork, body hardware, instruments and transmission parts are much harder to find, which makes completeness a major consideration when buying a project.

Collector Takeaway

The Series 345 Convertible Coupe deserves attention because it combines three facts rarely found together: Cadillac-built 353 V8 running gear, a short open body and production during the sharpest contraction of the American luxury-car market. The 345-A, 345-B and 345-C also form the final uninterrupted sequence of large-V8 LaSalles before the marque changed engines, proportions and engineering direction for 1934.

The right car is not necessarily the one with the brightest paint or the longest accessory list. It is the example whose open body is genuine, whose annual series is correctly identified, whose engine and chassis can be documented, and whose restoration respects the mechanical systems that make a Series 345 different from a later LaSalle. Preserve those elements and the car explains Cadillac's Depression-era strategy more convincingly than any showroom brochure could.