Downsizing in the automobile industry is the practice of redesigning a vehicle to retain the interior volume, and often the nameplate and styling of a larger car to a smaller, more efficient platform. It was common in the 1970s following the 1973 oil crisis.
General Motors was among the first to announce a downsize strategy for the whole company as a response to demand for smaller more efficient cars. An alternative strategy was to simply rebadge or mildly restyle smaller vehicles, as nameplates such as the Ford LTD and Plymouth Fury were applied to smaller platforms.
The term engine downsizing is used when the car itself remains the same size but the engine is reduced, with the aim of making the vehicle more efficient.
 General Motors
The first cars to be downsized were the 1977 full-size cars for Buick, Cadillac, Chevrolet, Oldsmobile, and Pontiac. Most models were left a foot shorter and averaging 750–800 lb (340–360 kg) lighter. This created a marketing problem, since the full-size cars had substantially less shoulder room than their predecessors, and were narrower and barely longer than GM's mid-size cars. This problem was solved by having sales advertisements mention any increases in headroom, legroom and trunk space while avoiding all mention of shoulder room. For the 1978 model year, the intermediate GM A platform was redesigned and downsized to near-compact dimensions. After the second gas crisis in 1979, the cars of the GM X platform were redesigned and replaced by front-wheel drive counterparts. By the end of the 1980s, nearly all cars produced by GM would be front-wheel drive. At the end of the 1996 model year, the B-platform was discontinued; the cars were shifted onto front-wheel drive platforms.
Size comparison between 76 and 77 Caprice
|1976 Caprice||1977 Caprice|
|Wheelbase||121.5 in (3,086 mm)||116.0 in (2,946 mm)|
|Overall Length||222.9 in (5,662 mm)||212.1 in (5,387 mm)|
|Width||79.5 in (2,019 mm)||75.5 in (1,918 mm)|
|Height||53.7 in (1,364 mm)||55.3 in (1,405 mm)|
|Front Headroom||38.9 in (988 mm)||39.0 in (991 mm)|
|Front Legroom||42.5 in (1,080 mm)||42.2 in (1,072 mm)|
|Front Hip Room||59.3 in (1,506 mm)||55.0 in (1,397 mm)|
|Front Shoulder Room||63.8 in (1,621 mm)||61.1 in (1,552 mm)|
|Rear Headroom||38.0 in (965 mm)||38.2 in (970 mm)|
|Rear Legroom–ins.||38.8 in (986 mm)||39.5 in (1,003 mm)|
|Rear Hip Room||59.7 in (1,516 mm)||55.7 in (1,415 mm)|
|Rear Shoulder Room||63.8 in (1,621 mm)||61.1 in (1,552 mm)|
|Luggage Capacity||18.9 cu ft (535 L)||20.9 cu ft (592 L)|
Unlike Ford or General Motors, Chrysler's full-size car sales did not rebound from the initial 1973 gas crisis. In 1974, Chrysler introduced its last all-new full-sized models (C-platform) for the time; a lack of development funds forced the company to focus on updating its compact, midsize, and personal luxury car lines. In 1979, as a response to General Motors and Ford, Chrysler replaced the C-platform with the smaller R-platform; however, the R-platform was considered outdated from the start, essentially a stretched version of Chrysler's midsize car platform, which dated to 1962. By the end of the 1981 model year, poor sales of all four R-body cars forced its discontinuation.
In 1982, Chrysler downsized many of its nameplates, as the M-platform took over the role of the company's largest car. However, it was no longer considered full size by EPA standards; it was introduced as the "compact" Dodge Aspen and Plymouth Volare in 1976. For mid-size cars, Chrysler replaced the Volare and Aspen with the K-car, a 6-passenger sedan that combined mid-sized interior room with compact exterior dimensions; its front-wheel drive layout was adopted in virtually all Chrysler cars into the 21st century. For the 1988 model year, Chrysler launched a full-size variant of the K-Car; Dodge also marketed a badge-engineered version of the Renault 25 as part of the Chrysler purchase of AMC. With the Dodge Dynasty, Chrysler New Yorker, and Chrysler Imperial, the company marketed the first 6-passenger full-size cars with front-wheel drive; a V8 engine was completely unavailable.
In the 1980s era of downsizing, Chrysler explored alternatives for large family vehicles. Declining sales along with lack of development funds led Chrysler to not include station wagons as part of the 1979 redesign of its full-size cars. After 1982, Chrysler sold a single station wagon, the compact K-Car. In 1984, the company introduced its first minivans; although largely based on the K-Car, the Plymouth Voyager and Dodge Caravan approached full-size wagons in terms of passenger and cargo carrying capabilities. By 1992, station wagons had vanished from the Chrysler lineup completely.
Alongside Chrysler, Ford introduced its own downsized full-size car platform in 1979. Like GM's downsizing, the Ford and Mercury models of Panther platform were over 15 inches (380 mm) shorter and 800 pounds (360 kg) lighter; the Ford LTD was left lighter and shorter than the "intermediate" LTD II. However, Ford retained the same amount of interior room from the 1978 model. The Lincoln Continental became the last full-size nameplate to undergo downsizing; formerly the largest mass-produced car in North America, it too became produced on the Panther platform for the 1980 model year.
In 1983, Ford used a strategy of badge engineering to further downsize certain models while avoiding the cost of developing new vehicle platforms. In an effort to move its full-size cars upmarket, the Panther-platform cars retained their top-of the line models (LTD Crown Victoria, Grand Marquis, and the Town Car) while the lower-trim models were moved onto the mid-size Fox platform. The Continental became a successor to the 1977-1980 Versailles, while the LTD replaced the Granada. As the Mercury Cougar shifted back to its traditional role of a personal-luxury car, the Marquis replaced the unpopular Cougar sedan and station wagon models.
During the mid-1980s, as front-wheel drive was adopted in mid-size cars, Ford replaced most Fox platform variants with those from the D186 platform; this was introduced by the 1986 Ford Taurus and Mercury Sable. With this introduction, Ford's era of downsizing had stopped. The Taurus was essentially the same size as the LTD it replaced; the only significant downsizing that happened was the discontinuation of the V8 engine seen (as an option) in the LTD/Marquis. Today, the current Taurus now serves as Ford's Crown Victoria replacement, although it has gained well over 1,000 pounds (450 kg) in 25 years of production. Conversely, after their 2011 discontinuation, the Town Car and Grand Marquis were left without any direct replacements (the latter marking the end of the Mercury brand).