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.
The Nova Super Sport was transformed from a trim option to a performance package for 1968. One of the smallest muscle cars ever fielded by Detroit, the Nova SS now included a 295 hp (220 kW) 350 cu in (5.7 l) V8 engine along with a heavy-duty suspension and other performance hardware, priced at US$312. Optional engines included two versions of the big-block 396 cu in (6.5 l) V8 rated at 350 hp (260 kW) and 375 hp (280 kW), which went for US$348. Both engines were offered with a choice of transmissions including the M-21 close-ratio four-speed manual, the heavy-duty M-22 "Rock Crusher" four-speed manual, or the three-speed Turbo-Hydramatic 400 automatic transmission. A total of 17,564 SS coupes were produced for 1968. Novas sported the SS badge until 1972. Front disc brakes were optional on the 1968 Nova SS.
Source: Wikipedia, 2014