The 1972 Chevelle seemed to be following in the tread marks of other muscle cars of the time, declining in power to meet emissions standards. A new rule had engines reporting their net horsepower rather than their gross, so power numbers fell through the floor. The 350-ci V8 was now rated at 175 horsepower, even though the engine did not change. The top engine was the LS5 available in the SS 454, rated at 270 horsepower. The exterior was not changed much from the 1971 model, except that single-unit front turn signals were introduced.