All 1971 Chevrolet engines featured lower compression ratios to permit the use of regular leaded, low lead or unleaded gasoline of at least 91 octane rating per GM corporate mandate in anticipation of the catalytic converters planned for 1975 and later models which necessitated the use of unleaded fuel.

A high-performance big block V8 was available in the form of the Turbo-Jet 454, which produced 365 hp in 1971, but power decreased as the years went along.

The 1970s marked the impact of the 1973 energy crisis with gasoline prices doubling from 1973 through 1979 and industry car sales plummeted 20 percent between 1973 and 1974.

Newly standard features included power front disc brakes, inside hood release, and a revised Astro-Ventilation system that utilized air distribution grills in the trunklid.

During the first months of the model year, the three-speed Turbo-Hydramatic automatic transmission was optional with all engines while the two-speed Powerglide could be ordered with the 250 6 or 350 V-8s.

Station wagons featured a 'clamshell' design where the rear power-operated glass slid up into the roof as the tailgate (manually or with power assist), dropped below the load floor.

[5] The Impala ragtop sold 6,456 units, placing fourth with just under 9% of the market, right behind the Corvette 6,508, and the Cutlass Supreme's 11,571, while remaining ahead of the Mustang's 6,401.

1973 Impalas featured a larger, shock-absorbing front bumper due to new federal mandates which required 5-mile-per-hour (8.0 km/h) impact protection.

Due to the passenger side airbag, ACRS-equipped Impalas featured a modified instrument panel from an Oldsmobile 88.

[8] One of the examples of an ACRS-equipped 1973 Impala was used on the television sitcom Seinfeld, where it was driven by Cosmo Kramer (played by Michael Richards) in several episodes.

The front end featured a new grille and headlight bezels, a new header panel, and a bumper with a drop down center section.

For 1974 the Custom Coupe was no longer a hardtop, with large fixed rear quarter glass and a thick B-pillar.

The Caprice model carried a new front end with a swept back style header panel with recessed headlight buckets, a new hood, and new fenders.

Catalytic converters were also introduced as were several new options, including an Econominder gauge package, intermittent wipers, and a divided 50-50 bench seat (with a choice of sport cloth or vinyl trim).

It featured an elk-grained landau vinyl roof (with a chrome band across the roof), a choice of special paint colors, sports-styled dual remote outside rearview mirrors, color-keyed wheel covers, a vinyl bodyside molding insert, and pin-striping.

This was the final year for the four-door hardtop sedan, the big block 454 V-8 now yielding 225 horsepower, and the station wagon clamshell tailgate.

Full-size cars made the most of their perimeter frame and full coil spring suspension to deliver a smooth ride.

The interior had such luxuries as simulated rosewood vinyl trim on the instrument panel, steering wheel, and doors.