Surely one of the more odd names the Feather Duster was a response to the fuel crisis and only offered in 1976. Plymouth offered the $50.56 Feather Duster Fuel Economy Package which turned your normal Duster into a Feather Duster. Dodge sold a similar but less remembered Dodge Dart Lite. Included in the package was a very tall 2.94:1 axle ratio, special exhaust, re-calibrated single barrel carburetor and distributor. In a quest to reduce weight aluminum parts where substituted for the hood, inner trunk, bumper mounts, intake manifold and transmission housing on the manual gearbox. This diet took 187lbs off the weight of a normal Duster. Transmission offerings where a four speed manual or three speed automatic. The result was advertised fuel economy of 24 mpg city and 36 mph highway but acceleration suffered. Quite impressive for a car of its size and era. On paper economy was quite close to the much smaller compacts.
About 20% of 1976 Dusters had the Feather Duster package and ironically became in demand later from racers who coveted their lighter weight so its not uncommon to see the original slant six engine ditched for a powerful V8 like the example pictured below.