All through the muscle car era, engines were getting larger and more powerful. Eventually, huge engines became prohibitively expensive and GM® executives put a cap on engine size. At the request of several dealers, the COPO® program was started to get around those restrictions. Dealers could specially order ZL-1s with 427 cu. in. (7.0 L) engines. The upgrade made the ZL-1 very expensive, but for some gearheads the power was worth the price. This kit features a detailed engine, air induction hood and full interior with separate side panels.