The Plymouth Duster introduced in 1970 was all Valiant from the cowl forward, but the rest of the car's sheet metal, save door skins, was completely different. The design incorporated a semi-fastback roof and a special rear valance with twin horizontal taillights, unusual for having no bezels. The door glass was operated by a totally new regulator mechanism, required to fit the much more radical tumblehome (reduced side glass radius), and the windshield was more steeply raked. For 1970 only, a small Valiant badge went on the front fenders just above the Duster badge.
The 1970 Duster was available in two models — the standard Duster and a performance-oriented Duster 340. Engine options were 198 cu in (3.2 L) and 225 cu in (3.7 L) versions of Chrysler's Slant Six, as well as the 318 cu in (5.2 L) and 340 cu in (5.6 L) LA-series V8s.
At midyear, a Gold Duster trim package was added. The Gold Duster package came with either the 225 Slant Six or the 318 V8. It also came with special "Gold Duster" badging, gold stripes on the sides and rear, wall-to-wall carpeting, pleated, all-vinyl seats, whitewalls, wheel covers, a deluxe insulation package, and a canopy vinyl roof. The Gold Duster was offered through 1975. Total sales in 1970 came to 217,192, of which 24,817 were equipped with the 340 engine.