In 1941 both engines were offered on each series so to differentiate between the two the second digit was used to denote the number of cylinders, so the Dynamic 70 was replaced with the Dynamic 76 and 78. In 1942 sales literature started referring to the Series 70 as the Dynamic Cruiser 76 and 78. In 1948, when the Series 60 was renamed the Dynamic the "Cruiser" tag was dropped from the Series 70 and it was once again named the Dynamic 76 and 78.
For the 1940 model, Oldsmobile was the first auto manufacturer to offer a fully automatic transmission, called the Hydramatic, which featured four forward speeds. It had a gas pedal and a brake—no clutch pedal. The gear selector was on the steering column.
Available through the option sheet for $100 was the increasingly more popular Hydra-Matic four-speed automatic, coupled with a 3.63:1 rear gear ratio, which period advertising claimed increased fuel efficiency by 10-15 percent.
Enveloping the mechanicals was the attractive 211-inch-long body. In Deluxe trim, upgrades included larger 15 x 5.50-inch wheels wearing 7.00-15 tires and chrome trim rings, a chrome hood ornament incorporating a stylish plastic insert, and chrome "speed lines" that adorned the front and rear fenders behind each wheel opening; gravel shields were optional. Those built late in the model year received less trim due to a short supply of chrome; missing items tended to include fender trim, while fender grilles and dash trim were actually painted stamped steel.
Dynamic art deco themed interiors featured cloth seating, front armrests, floor carpeting, a right-hand sunvisor and Fisher No Draft ventilation. The Deluxe package added upholstery with thicker foam rubber seat cushions and armrests, a three-spoke steering wheel, a clock mounted on the glovebox door and an instrument cluster with "clear vision plastic facing."
Engine 257 cu in (4.2 L) Oldsmobile I8
Transmission 4-speed Hydra-Matic automatic
Wheelbase 125.0 in (3,175 mm)
Length 1941: 211.0 in (5,359 mm
Curb weight 3,500–3,700 lb (1,600–1,700 kg