1980 saw a new, shrunken Thunderbird that was little more than a sedan with nicer trim; though in post-fuel-crisis America, these vehicles could be thought of as intermediate-sized, rather than compacts. The 1980 Thunderbird was a unibody car, weighing 800 lb (363 kg) less than the 1979 model, and was 17 in. (432 mm) shorter. It was based on the new Fox platform, and the lighter weight resulted in better gas mileage.
   The Box Birds were not well received by the general public, and were considered by many to be only a Ford Fairmont with Thunderbird styling. Mercury's own version of this car was the Cougar. The Box Birds possesed a unique body style that was all their own, with squarish upright lines favored by Ford design vice-president Eugene Bordinat.
   They were luxuriously appointed, and fuel efficient for their size. The six cylinder models were known to get up to 30 US mpg. The 1980–1982 Thunderbirds offered flip-up headlights, and were the only Fox-body cars to have them. Digital instrumentation was also available, along with a variety of trim packages from which to choose. Though somewhat underpowered, they drove well, could easily keep pace with traffic on the open road, and offered considerable luxury in their size class.
   Power was somewhat scarce due to the new emissions control laws coming into effect in the late 1970s.