Use the online decoder and websites only as a guide but not for the truth.
As another member stated, the feather duster was only available with a 225. The ‘G’ engine code in your door vin sticker indicates that car came with a 318 from the factory so wasn’t a real feather duster to start with.
https://www.hamtramck-historical.co...rshipDataBook/1976/76-Valiant-Duster_0018.jpg