1973 Buick Century Engine: 7.5L V8; Standard Rotation; Optional Non-Thermal Fan Clutch;. 1973 Buick Century Submodel: Wagon; Engine: 5.7L V8; Standard Rotation; Optional Non-Thermal Fan Clutch;. 1974 Buick Century Submodel: Wagon; Engine: 5.7L V8; Standard Rotation; Optional Non-Thermal Fan Clutch;.