The 1972 Corvette featured only small changes from the previous model year, but it is now known as the last model to have both front and rear chrome bumpers. It was also the last year for the RPO-LT1 and RPO-ZR1 engines. A 454 ci big block motor was standard, and rated at 270 horsepower. While this may appear to be a large drop from the 365-horsepower rating of 1971, it actually was not: horsepower became measured for constancy rather than peak performance.