The 1934 Cadillacs were completely restyled and mounted on an entirely new chassis, but used the same basic engines as in 1933.

Bodies

• Bodies on the Series 10 and 20 cars were built by Fisher.
• Bodies on the V-8 Fleetwood Series were shared with the twelves and sixteens.
• Styling emphasized streamlining including concealment of all chassis features except the wheels
• Body construction was improved for better insulation against engine heat and reduction of engine, road, and wind noise.
• Bumpers were a stylish but ineffective biplane design, mounted against telescoping springs.
• The grill was Vee shaped and sloping, set into a painted shell.
• Although restricted use of chrome was a feature of the overall ornamentation, a chrome plated radiator shell was available as an option.
• Horns and radiator filler cap were concealed under the hood.
• Teardrop Guide Multibeam headlights were mounted on streamlined supports attached to the fenders.
• Parking lamps were mounted in the headlight supports.
• Airfoil shaped front fenders were brought low over the chassis.
• The hood sills were high, with the entire fender shape molded into the radiator shell.
• A curious horizontal crease broke the nose contour of the fenders.
• Hoods extending nearly to the windshield carried shutter type louvers in the side panel.
• Windshields were fixed and steeply sloping; 18 degrees flat on Fisher bodies, 25 degrees flat or 29-1/2 degrees Vee on Fleetwood bodies.
• Cowl vents opened toward the windshield; one vent on flat windshield bodies, two vents projecting through openings in the hood on Vee windshield bodies.
• Bodies were two inches lower than on previous models.
• Added passenger space in the front compartment was achieved by moving the hand brake lever to the left of the driver, under the instrument panel.
• On twelves and sixteens, the gearshift lever was moved forward to the clutch housing.
• Rear fenders were airfoil shaped and carried rear lights which matched the headlights.
• The gas tank filler on Fisher bodies was on the left side at the rear of the body; on Fleetwood bodies in the left rear fender.
• All bodies featured a beaver tail rear deck which completely covered the chassis.
• On Fleetwood bodies, the spare was concealed inside the rear deck, unless optional fender mounts were specified.

Chassis:

• Significant changes in chassis design resulted in improved riding and handling plus decreased driver fatigue.
• The new independent "knee action" front suspension with coil springs and center point steering resulted in greatly reduced unsprung weight.
• Front shocks were now an integral part of the suspension; the shock arm being the upper suspension arm.
• An inverted steering box, mounted on the outside of the frame, was used on Fleetwood bodied cars.
• Hotchkiss drive replaced the torque tube drive.
• Rear brakes were operated by pull rods and cables.
• A new frame of X design added to chassis strength and allowed for the reduction in overall vehicle height.
• A stabilizer bar to control body roll in turns was added at the rear of the chassis.
• The brake and clutch pedal assembly was relocated from transmission to frame.
• Mufflers on Fleetwood bodied cars were relocated to the outside of the frame.
• In Fisher bodies, the battery was under the front seat, on the right side.
• In the Fleetwood bodies, the battery was under the right front fender and was removed from underneath.

Engine

• Engine changes were few, but horsepower was increased.
• All engines used Lynite Aluminum pistons.
• Compression ratios were increased.
• Intake ducting to the carburetor air cleaner was extended to the radiator casing, providing cold, dense air rather than the hot air in the engine compartment.
• The combination of Aluminum pistons, cold intake air, and higher compression with improved fuels resulted in increased horsepower and engine speeds.
• Detail changes in the V-8 engine included a change to the Detroit Lubricator Carburetor, use of dual valve springs, discontinuation of the oil filter, and solenoid starter control with starter button on instrument panel.
• One V-8 engine change to be appreciated by anyone removing a cylinder head was the change from head studs to cap screws.
• The change was actually made so that the heads could be turned before lifting, so as to clear the hood shelf.
• Another change, not necessarily appreciated was the elimination of provision for hand cranking.