the longest non-commercial production car ever built in the US.

 the 1973 Imperial was 19.6 feet, 235 inches long, which made it the longest postwar (non-limousine) production car and the third longest production car ever, 4" longer than the 74-76 Pontiac Grand Safari station wagon! 

https://www.autoevolution.com/news/5-of-the-longest-american-passenger-cars-ever-mass-produced-239155.html