When the Cadillac Coupe and Sedan de Ville shrank by 1,000 lbs and an entire foot in length for 1977, the sales numbers only grew fatter.

Here was a genuine challenge for Cadillac. For decades the GM premium car division had been selling cars on the premise that luxury meant bigger and heavier, and now the brand was making an 180-degree bootleg turn. In response to CAFE (Corporate Average Fuel Economy) standards, rising gasoline prices, and the growing popularity of smaller luxury cars from Europe, the Coupe and Sedan de Ville, Cadillac’s biggest sellers, were doing on a crash diet for 1977. Could traditional Cadillac buyers be persuaded to accept the smaller cars, or would they turn their backs on America’s leading luxury car brand?

Coupe de Ville 

In retrospect, GM engineers did a remarkable job in right-sizing the corporate C-body platform (also shared by Buick and Olds) to meet the new realities. Body-on-frame construction was retained, but with the wheelbase reduced from 130 inches to 121.5 inches, while  overall length shrank 9.5 inches to 221.2 inches and total width by 3.4 inches. Yet with a three-inch bump in roof height and more careful packaging, interior legroom, headroom, and trunk capacity were actually increased. While this new de Ville was considerably smaller, it wasn’t evident in the cabin.

Sedan de Ville (left) and Coupe de Ville interiors 

The weight reduction was an equally remarkable 1,000 lbs, achieved with a lighter but stronger perimeter frame and thinner steel and glass. The hulking 500 cubic-inch Cadillac V8 went under the knife as well, with the block’s deck height reduced from 10.8 inches to 10.15 inches and casting walls pared down wherever possible. Bore and stroke were reduced from 4.30 x 4.30 inches to 4.08 x 4.06 inches, shriveling the displacement to a mere 425 cubic inches. Here the goal was improved fuel economy along with the weight reduction.

However, the loss in net output was less than one might expect: from 190 hp and 360 lb-ft of torque to 180 hp and 320 lb-ft. And with 1,000 fewer pounds to haul around, the de Ville’s power-to-weight ratio actually improved. An optional Bendix fuel injection system ($783) replaced the standard Rochester Quadrajet four-barrel carburetor, boosting the output to 195 hp. Bendix was actually the pioneer in electronic fuel injection back in 1957, holding a number of patents (see our feature here), and the system first appeared at Cadillac in 1975.

Sedan de Ville

Vice-president of design Bill Mitchell was no particular fan of GM’s corporate downsizing program, likening the project to “tailoring a suit for a dwarf.” Still, studio chief Wayne Kady and his staff successfully transplanted all the familiar Cadillac styling elements to the smaller package. It’s fair to say that visually, the new de Ville was every inch a Cadillac, but with fewer inches. In the new de Ville, here was “the next generation of the luxury car,” Cadillac declared.

The radical surgery was a success. Even with the reduction in size and weight, prices for the fifth-generation de Ville rose by 6 percent, roughly the inflation rate at the time. Yet sales took off, posting an increase of nearly 30 percent to 234,171 cars—138,750 Coupes and 95,421 Sedans. In fact, ’77 was the best year in history for de Ville sales since the 1949 introduction. This same basic package would remain in production through 1984, when it was replaced by a still smaller de Ville on a transverse front-drive platform.