sentences:  Engines with displacements between have been classified as both small-block and big-block, depending on the particular manufacturer's range of engines.Big-block engines reached their zenith with the Cadillac 500 engine used in the 1970 Cadillac Eldorado coupe.During the 1970s, due to the oil crises and the gradual tightening of emission-standards, big-block V8s were affected and as a result their use in passenger cars decreased as manufacturers began to phase them out for more efficient designs.