The 1968 models were fully redesigned with an extensive restyle on a longer 111-inch wheelbase that gave Chevy's compacts a chassis that was just one inch shorter than that of the midsize Chevelle coupe. The station wagon and hardtop sport coupe were discontinued, the former in line with an industry trend which left AMC the only American maker of compact station wagons until Chrysler rejoined the market in 1976 (the 1966-70 Ford Falcon wagon was actually a midsize, using a bodyshell identical to the Fairlane wagon's). One notable change was the front subframe assembly — as compared with Ford, Chrysler and AMC, in whose cars the entire front suspension was integrated with the bodyshell, a separate subframe housing the powertrain and front suspension (similar to the front part of the frame of GM's full-size, full-framed vehicles) replaced the earlier style. Although the front subframe design was unique for the Nova, the Camaro introduced a year earlier was the first to incorporate such a design; the redesigned Nova was pushed a year ahead to 1968 instead of 1967. The sales brochure claimed 15 powertrain choices for coupes and a dozen for sedans. Options included power brakes and steering, Four-Season or Comfort-Car air conditioning, rear shoulder belts, and head restraints. There were a few Chevrolet Novas built with the 194 ci(3.1 L), the same motor that had been used in the previous generations of the Chevy II.
Sales of the 1968 Chevy Nova fell by half. Chevrolet dropped the Chevy II portion of its compact car's name; it was now known simply as the Chevrolet Nova. The 153 cu in (2.51 L) four-cylinder engine was offered between 1968 and 1970, then was dropped due to lack of interest (besides its other usage in the Jeep DJ-5A a.k.a. the Postal Jeep) and to clear the field for the Vega. Far more popular were the 250 cu in (4.1 L) six-cylinder and the base 307 cu in (5.03 L) V8, which replaced the 283 cu in (4.64 L) V8 offered in previous years. At mid-year, a semi-automatic transmission based on the Powerglide called the Torque-Drive (RPO MB1) was introduced as a low-cost option (~$100 less than the Powerglide) for clutchless motoring. The Torque-Drive transmission was only offered with the four and six-cylinder engines. The two-speed Powerglide was still the only fully automatic transmission available with most engines, as the more desirable three-speed Turbo-Hydramatic was only available with the largest V8 engines.
As with other 1969 GM vehicles, locking steering columns were incorporated into the Nova. Simulated air extractor/vents were added below the Nova script, which was relocated to the front fender behind the wheelwell instead of the rear quarter panel. The 350 cu in (5.7 L) V8 with four-barrel carburetor that came standard with the SS option was revised with a 5 hp (4 kW) increase to 300 hp (220 kW), while a two-barrel carbureted version of the 350 cu in (5.7 L) V8 rated at 255 hp (190 kW) was a new option on non-SS models. The SS option price remained US$312 A new Turbo-Hydramatic 350 three-speed automatic was made available for non-SS Novas with six-cylinder and V8 engines, although the older two-speed Powerglide continued to be available on the smaller-engined Novas. 1969 SS models were the first Nova SS models to have standard front disc brakes.
The 1970 Nova was basically a carryover from 1969. The side marker and taillight lenses for the 1970 Nova were wider and positioned slightly differently. This was the final year for the SS396.( Actually a 402 Cubic in. engine now) All other engines were carried over including the seldom-ordered four-cylinder which was in its final year.
1971 Novas were similar to the previous year. The 396 cu in (6.49 L) engine was replaced with the 350 cu in (5.7 L) in the SS model. 1971 also saw the introduction of the Rally Nova, a trim level that only lasted two years (until it resurfaced in 1977). The Rally kit included black or white stripes that ran the length of the car and around the back, a Rally Nova sticker on the driver's side of the hood, Rally wheels, multi-leaf rear springs, and a "sport" body colored drivers side mirror that was adjustable from the interior. The well-hyped Vega stole sales from the Nova this year, but the compact soon would enjoy a resurgence of popularity that would last deep into the 1970s.
The 250 cu in (4.1 L) six-cylinder engine was now the standard Nova engine with the demise of the 153 cu in (2.51 L) four-cylinder and 230 cu in (3.8 L) six-cylinder engines. The 307 cu in (5.03 L) and 350 cu in (5.7 L) V8s were carried over from 1970 and all engines featured lowered compression ratios to enable the use of unleaded gasoline as a result of a GM corporate mandate that took effect with the 1971 model year.
The 1972 Nova received only minor trim changes. The Rally Sport option with special suspension returned and was a rather popular choice, with 33,319 sold. Super Sport equipment went on 12,309 coupes, some of which also had the Rally package. Nova production moved to Norwood, Ohio, where it would be assembled alongside the Camaro. At mid-year a sunroof option became available on two-door models. Also, the optional Strato bucket seats available on coupes switched from the previous low-back design with adjustable headrests to the high back units with built-in headrests introduced the previous year on Camaros and Vegas. The Rally Sport option with special suspension returned and was a rather popular choice, with 33,319 sold. Despite the lack of change, Nova had its best sales season in years, with production of the 1972 models reaching 349,733. Of these, 139,769 had the six-cylinder engine.
The 1973 model year introduced a hatchback bodystyle based on the 2-door coupe. The front and rear of the Nova were restyled, following a government mandate for vehicles to be fitted with front and rear bumpers capable of absorbing a low-speed impact of 2.5 mph (4.0 km/h). To go along with the bigger bumpers, stylists gave the Nova a new grille with a loosely patterned crosshatch insert and parking lights located inboard of the headlights. In 1974, they could absorb 5 mph impacts.
An SS option remained available, but it was merely a $123 dress-up package that included a blackout grille and Rally wheels. It could be ordered with any of the Nova engines. 35,542 SS packages were installed, making 1973 the best-selling year for the option. A modified rear side window shape was also introduced, eliminating the vent windows on both two- and four-door models. A revised rear suspension was adapted from the second generation Camaro with multi-leaf springs replacing the mono-leaf springs used on Novas since the original 1962 model. By this time, six-cylinder and V8 engines were de rigueur for American compact cars, with the 307 cu in (5.03 L) and 350 cu in (5.7 L) V8s becoming fairly common. The 1973 Nova with a six-cylinder engine or 307 cu. in.(5.0 L) V8 were among the last Chevrolets to be offered with the two-speed Powerglide automatic transmission, which was in its final year. A dressy Custom series joined the Nova line and a Custom hatchback listed for $2,701 with a six-cylinder engine. That was $173 more than the six-cylinder base-model two-door hatchback. Air conditioning added $381. Every 1973 Chevrolet Nova got side guard door beams and additional sound insulation, as well as flow-through ventilation systems. A sunroof could be installed, and fold-down rear seats were available.
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 hoodscoop 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.