71 Duster 340 Fender Tag

I'm no expert so I'll refer you to this link. Lot's of folks use MyMopar as a reference for everything Mopar.

1969-1971 Fender Tag / Broadcast Sheet Codes List – MyMopar

Be sure to introduce yourself in the Welcome Wagon portion of the site. Post pics of your Duster in there and it'll be sure to be given it's proper and deserved attention. Welcome aboard.