I have to disagree with that. 318's were not a Feather Duster or Dart Lite option. But the package with special 6 cyl. could be ordered with an automatic or a 4-speed O.D. "Regular" 6 cyl. were used in the "regular cars". The only related statements in print that I can find at the moment are at the bottom of this article where the author states: "Along with the usual slant six engine".
... this about 1/2 way down the page: "The 1976 Feather Duster was an engineering (if not marketing) success, featuring many lightweight parts including some aluminum body panels. It had a slant-six with gas-miser tuning and a special exhaust that could achieve over 30mpg."
.... and this near the bottom in the "1976" section: "Another interesting new package was the "Feather Duster", which was available only as a Slant Six"
.....and one more, just past 1/2 way down the page: "A Feather Duster was introduced which replaced many of the body components with aluminum, resulting in nearly 200 pound weight loss for the vehicle. It was outfitted with the six-cylinder engine, special exhaust system, and promoted as a light-weight, fuel efficient vehicle."
