For 1974, the Chevrolet Nova got larger parking lights and new bow-tie grille emblems, as well as modified bumpers that added two inches to length and helped cushion minor impacts. The Powerglide was replaced by a lightweight version of the three-speed Turbo-Hydramatic 350 ( THM 250 ) already offered with the 350 cu in (5.7 L) V8, which was the only V8 offered for 1974. Nova sales continued the surge they had enjoyed since 1972 and approached 400,000 cars for 1974. Six-cylinder Novas were the fastest gainers, as sales of V-8 Novas declined. These were the years of the first energy crisis as Middle Eastern countries cut back on oil exports. After waiting for hours in gas lines and fretting about the prospect of fuel rationing, thrifty compacts looked pretty good to plenty of Americans. Nova fit the bill.
The 'Spirit of America' Nova was introduced in 1974. In anticipation of the US bicentennial in 1976, the limited edition Nova Coupes were painted white and featured blue and red accent stripes as well as red and blue interior carpets and fabrics. Oldsmobile and Buick entered the compact car market; both the Apollo and Omega debuted, using the same bodystyles from the Nova lineup. Additional options were included on these Nova-like models, such as lighting under the dashboard and in the glove compartment. Pontiac's final GTO of this era was based on a facelifted 1974 Ventura coupe, itself based on the Nova, but fitted with a shaker hood scoop from the Trans Am.
Novas and all 1974 cars were fitted with a weight sensitive relay within the front seat that prevented the vehicle from being started until the driver's seatbelt had been fastened, following a safety mandate from the NHTSA. Later, a law passed by Congress repealed the mandate requiring this type of device, declaring that it infringed on a driver's freedom of choice, and allowed owners of 1974-model cars to have the seat belt interlock bypassed. The devices were not included in future Nova models. Along with this controversial seat belt interlock, a new, more convenient "inertial reel" one-piece lap/shoulder safety belt assembly was standard for both front outboard passengers, along with a plastic clip attached to the headrest to guide the belt across the wearer's shoulder.
Source: Wikipedia, 2014