LaSalle

1934–1938

Beginning with the 1934 model year, a significant portion of the LaSalle, now called the Series 50 Model 350, was more closely related to the Oldsmobile L-Series, Buick Series 40 and Buick Series 50 while sharing an appearance with the senior Cadillac Series 355s. This was marked by a shift to the Oldsmobile- and Buick-based B platform. Again, Earl's work with the LaSalle resulted in a graceful vehicle, led by an elegantly thin grille that now concealed the previously exposed radiator, which was shared with Cadillac and Pontiac for that year. Earl's other contribution was the modern, airplane-styled, semi-shielded portholes along the side of the hood. All bodies were now made by Fleetwood. 1933 was the first year all GM vehicles were installed with optional vent windows which were initially called “No Draft Individually Controlled Ventilation” later renamed "Ventiplanes" which the patent application was filed on Nov. 28, 1932. It was assigned to the Ternstedt Manufacturing Company, a GM subsidiary that manufactured components for Fisher Body and they were introduced on the Series 50 in 1934.

The Series 50 was also no longer available with a V8, which was a distinction shared with all Cadillacs, and now only available with an Oldsmobile sourced flathead inline-eight, while Buick continued to offer the more technologically advanced overhead valve straight-eight engine exclusive to Buick. The LaSalle was the first Cadillac to use hydraulic brakes sourced from Bendix and various components were sourced from within different GM Divisions in order to cut production costs. The Oldsmobile engine was not assembled by Oldsmobile then supplied to the LaSalle factory, instead the parts were sent to the LaSalle factory and assembled by Cadillac-trained LaSalle assembly teams to authentically declare it was manufactured by Cadillac engineers. The LaSalle sales department further invited clients to witness the cars being manufactured and listed the different companies that sourced various items that were used to manufacture the 1934 LaSalle.

This LaSalle Series 50 Model 350 listed at US$1,550 ($37,304 in 2025 dollars ) for a choice of coupes, sedans or convertibles and was now priced US$1,000 ($24,067 in 2025 dollars ) below the least expensive Cadillac. Its mission was not to fill a price gap, but to keep the luxury-car division out of the red. But as the economy began to recover, the LaSalle did not, at least not commensurate with the economy. Sales were 7,195 in 1934, 8,651 in 1935 and 13,004 in 1936 while Buick appeared to be more attractive yet frugal.

To further emphasize that the 1935 LaSalle was improved from the previous model, the name was, again, changed to Series 35-50, dropping the "model" designation, while the vehicle was largely the same with the usual appearance, options list changes, and mechanical advancements. Meanwhile, the Packard One-Twenty had been introduced in 1935 and was very successful. For 1936 the LaSalle was renamed the Series 36-50 and had additional competition from the Lincoln-Zephyr, introduced in 1936. The 1937 LaSalle was called the Series 37-50, a naming convention that would continue with the last LaSalle Series 40-50 and 40-52.

For 1937, Cadillac made the LaSalle its own again, giving it the designation Series 37-50 and the 322 cu in (5.3 L) monobloc V8 of the Series 60, new styling, a lower price range, and a heavy promotion emphasizing that the car was completely Cadillac-built. It was too late. Model year sales of 32,000 LaSalles was a great improvement, but it remained far behind the Packard.

A 1934 LaSalle Series 50 Model 350 was chosen as the Pace Car for the Indianapolis 500, and a 1937 LaSalle Series 37-50 convertible also served as an Indy 500 Pace Car.

1939–1941

In its final years, the LaSalle Series 39-50 was once again more Cadillac-like in its appearance and details, and was essentially identical to the Cadillac Series 61. The narrow radiator grille opening was retained and was flanked by additional side grille work which aided in heat dissipation from the engine. Headlights, which had moved down and been secured to the body between the grille and the fender, were again attached to the radiator shell. LaSalle also added a sunroof, marketed as the "Sunshine Turret Top". Sales climbed from 15,501 in 1938 to 23,028 in 1939.

The final 1940 LaSalles were introduced in October 1939 with a full array of semi-custom body styles, as it had in its first year, including a convertible sedan. Earl oversaw this redesign. The LaSalle emerged with a smooth-flowing design, its thin radiator flanked by a series of thin chrome slots. In its final year, sales of the LaSalle reached the second-highest level ever at 24,133. In addition to the Series 40-50, there was also the lower, wider Series 40-52 Special using General Motors' new "Torpedo"-style body.

1941

By the time the decision was made to drop the LaSalle, at least three wood-and-metal mockups had been made for potential 1941 LaSalle models. One was based on the notchback GM C platform, which ended up being shared by the Cadillac Series 62, the Buick Roadmaster and Super, the Oldsmobile 90, and the Pontiac Custom Torpedo. A second was based on the fastback GM B platform, which was eventually shared by the Cadillac Series 61, the Buick Century and Special, the Oldsmobile 70, and the Pontiac Streamliner Torpedo. A third was a modified notchback design, derived from the fastback B-body, but described as "A-body-like", that was finally used by the Cadillac Series 63. Any or all of these could have ended up being part of the next LaSalle line. However, it is widely believed that of the three, the third design was most likely to have been a LaSalle, with that platform being assigned exclusively to LaSalle, and that the second design, whose platform was shared with the Series 61, was the next-most-likely. In 1941, sales of the Cadillac Series 61 and 63 were 29,258 and 5,030, respectively.

In retrospect, LaSalle sales initially had exceeded Cadillac's since 1933, but since its introduction in 1935, the medium priced Packard One-Twenty had consistently outsold the LaSalle by an average of 72 percent over the six-year period 1935–1940 inclusively. It was decided to fold the LaSalle into the more prestigious Cadillac marque. LaSalle did not have the time to develop a prestigious name before the onset of the Great Depression and did not have the opportunity afterward. The Great Depression, combined with LaSalle's stalling sales numbers, caused Cadillac to rethink its companion make. Both Buick and Oldsmobile had eliminated the Marquette and the Viking in 1930, their second model year. Cadillac also saw sales of its cars losing ground, as confirmed Cadillac buyers tried to trim pennies by buying the less expensive LaSalle. LaSalle sales also were falling, from a high of 22,691 models in 1929 to a low of 3,290 in 1932.

While the introduction of LaSalle showed there was a market for a luxury car that was more conservative in appearance and price, GM already had Buick which filled that role very successfully. The attention given to LaSalle could have been invested in Buick as the mainstream luxury brand, and concentrated on Cadillac being more elusive and unique to protect the brand image. The introduction of the "Art and Colour Section" headed up by Harley Earl and a shared design theme in all GM products further complicated the brand distinction between the original brands in that the only differences among Oldsmobile, Buick, LaSalle, and Cadillac were exterior design appearance, wheelbase length, and colors, while charging extra due to marketing and pricing objectives.

The LaSalle name was raised again when Cadillac was developing a new small luxury sedan, but it was passed over in favor of Cadillac Seville. Early mockups of what was to become the 1963 Buick Riviera were badged "LaSalle II," as the Cadillac division was being considered for production of this successful personal luxury car.