The Duster was not changed significantly for 1972. New surface-mount sidemarker lights replaced the previous flush-mount items, the taillamps became larger, one-piece units. The power rating of the 340 V8 was reduced from 275 bhp (205 kW) to 245 hp (183 kW) due in part to a reduction in compression ratio from 10.2:1 to 8.5:1, as well as changing the intake valves from 2.02 in (51 mm) to 1.88 in (48 mm). All horsepower rating numbers, even on unchanged engines, decreased for 1972 due to a new rating protocol. Chrysler's electronic ignition became standard on the 340 models in 1972.
Source: Wikipedia, 2012