The term 'OLD PLYMOUTH MODEL' refers to three classic cars produced by the American car manufacturer Plymouth in the 1970s. The first is the DUSTER, a two-door coupe with a six-cylinder engine that was produced from 1970 to 1976. The second is the RELIANT, a four-door sedan with a seven-cylinder engine that was produced from 1971 to 1981. The third is the GTX, a two-door coupe with a three-cylinder engine that was produced from 1967 to 1971. All three models were popular for their performance and style.