Email alerts available. Gateway Classic Cars Ft. Lauderdale showroom is proud to offer this one of one 1970 Moulin Rouge and Black 1970 Plymouth Duster 340. Find 9 used 1970 Plymouth Duster as low as $23,995 on Carsforsale.com®. New York, NY This is originally a 340 plymouth duster,now running a factory rebuilt 360 engine.shows … The Duster coupe provided the compact-sized Plymouth Valiant with a sporty body style to attract customers. More listings are added daily. The car was a $15 million effort to update the compact Valiant for the 1970 model year. There are 10 1970 Plymouth Dusters for sale today on ClassicCars.com. Shop millions of cars from over 21,000 dealers and find the perfect car. History. The Valiant badge appeared only on the first model year Dusters, and continued to be used on all the companion 4-door sedan and 2-door Valiant Scamp hardtop models.