General Motors downsized its full-size cars for the 1977 model year, but the Oldsmobile Custom Cruiser wagon (sibling to the Chevrolet Caprice and Pontiac Catalina Safari wagons) remained a big, comfortable hauler of cargo and humans. Here's a magazine advertisement for the 1979 version, showcasing its ability to be loaded with enough boxes of eggs to feed breakfast to a medium-sized city.

1979 oldsmobile custom cruiser magazine advertisement
General Motors

Peak Wagon in the United States was two years in the rear-view mirror by 1979, but wagons still sold well and Oldsmobile would remain one of Detroit's major wagon players for quite a few more years to come.