Cadillac redesigned its entire line in 1971, softening the outline and lowering and lengthening the remaining nine models in the lineup. The pillared four-door sedan was replaced by a four-door hardtop in the Sedan de Ville and new Calais line, while the Fleetwood Sixty Special and long-wheelbase Fleetwood Seventy Five retained central pillars. The only convertible offered was now in the redesigned front-wheel drive Eldorado.

The Calais and DeVille rode on a new 130-inch wheelbase, the Fleetwood Sixty Special was 133 inches long and the nine-passenger Seventy Five was stretched to 151.5 inches. The Fleetwood Seventy Five was now a massive 20-feet long. Chassis were strengthened and the 472-cubic inch V8 was now standard, except for the Fleetwood which used a 500-cubic inch V-8. By cutting down the front and rear fenders and carrying the hood line through to the rear the new cars were lower and more elegant than their predecessors.

A three-month strike at GM began just when the new models were introduced and new cars didn’t start reaching customers until early 1971. As a result production of the DeVille models fell from 181,719 to 135,426 divided almost 50/50 between Coupe and Sedan de Villes, almost all with vinyl roofs. The lower level Calais model attracted only 6,929 buyers, evenly split between coupes and sedans and lacking vinyl tops. The 1971 Sedan de Ville was the most popular luxury car in the world, but reduced compression ratios cut the power drastically.

In 1972 Cadillac celebrated its 70th anniversary with minor changes, following the two-year plan. The big square grille was still protected by over-riders, but grille bars were now horizontal instead of squared. Bumpers were now beefed up to withstand 5-mph impacts. In common with other U.S. manufacturers, Cadillac now rated cars by net horsepower and the 472 cubic inch V-8 was rated at only 220 bhp. All Cadillacs included a full range of power options and air conditioning, with leather or brocade interior. Sales totaled 194,811 units. Once again, the largely identical low-line Calais attracted far fewer, with only 7,775 buyers.

Bumper regulations hit home in 1973, along with the gas crisis, and the new Cadillacs boasted massive 10 mph front bumpers that were attached to the grille. The grille and bumper were mounted on pistons which could retract several inches. Fragile rubber strips separated the bumpers from the body. Cadillac delivered its five millionth car on June 27 - a blue sedan de Ville, and a total of 216,243 DeVilles were sold, with the coupe outselling the sedan for the first time.

By 1974 the gas scare had passed and buyers were back buying big cars. The Cadillac DeVilles had grown longer with even bigger energy absorbing bumpers. Air bags were offered as an option for the first time, a high energy ignition system was fitted and the instrument panel redesigned. Coupe de Villes now had a fixed rear side window, similar to the Eldorado coupe. Glitzy Cabriolet and d’Elegance packages were offered, the latter with a velour interior and deep pile carpet, and it was possible to combine both. Coupe de Villes now outsold the sedans two-to-one with 112,201 coupes to 60,419 sedans, while Calais sales skidded to 6,773, with the same proportion of coupes and sedans.

In 1975, rumors of a new small Cadillac came to fruition in the mid-year Seville, based on the Chevrolet Nova platform. Electronic fuel injection was optional and all Cadillac models gained square headlights. The DeVille and Calais four-doors received a third window in the C-pillar. The egg-crate grilles were now much finer. Moon roofs were now offered and side “cornering” lamps fitted to front fenders. The year was marked by a significant recession and DeVille sales dropped to 173,570, while Calais sales rose slightly to 8,300. Coupes outsold sedans two-to-one in both cases.

The final year for the biggest GM body series was 1976, which also saw the demise of the unloved Calais line. It was also announced as the last year for a convertible, and 200 Eldorado convertible buyers paid extra, unaware that convertibles would return in 1984. An improved door locking system was offered and wire-wheel covers were optional on all models. Coupe de Ville sales totaled 114,482 units while sedans trailed at 67,677. Calais recorded 4,500 coupe sales and only 1,700 sedans. In 1977, Cadillacs would be downsized to match the Seville.