1981

Changes to the standard (Series 30) Eagle lineup for 1981 were notable. The GM 2.5 L Iron Duke I4 became standard equipment, as the 4.2 L I6 became optional. All Eagles took on a new plastic eggcrate-style grille divided into 24 squares at the front. The Eagle name moved to the grille header bar. Bumpers were updated so that their end caps flowed smoothly into the Krayton plastic wheelcarches and rocker panel trim. The Sport package, carried over from 1980 on all three body styles, used the Spirit's hood and grille header bar trim starting in 1981.
Two smaller subcompact models, the AMC Eagle Kammback, based on the AMC Spirit sedan (nee Gremlin), and the sporty Eagle SX/4, based on the Spirit liftback, debuted as "Eagle Series 50" models. The Kammback and SX/4 came standard with GM's 2.5 L "Iron Duke" 4-cylinder engine, 4-speed manual transmission, and power steering. The Series 50 Eagles reflected the styling updates that the larger Series 30 models showed for 1981. The SX/4 model was available with a Sport package, as well.
At the beginning of the model year, all Eagles carried over the new-for-1980 permanent all-wheel drive system with viscous fluid coupling, which protected the suspension or driveline components from wear during dry weather use. A "Select Drive" option, which allowed the Eagle to run in 2-wheel-drive (RWD) mode and be switched to 4-wheel-drive via a dashboard switch, was offered as a fuel economy measure at midyear. Select Drive required the vehicle to be stationary when switching between 2-wheel-drive and 4-wheel-drive.