The 1969 ZL-1 Corvette came equipped with an entirely new big-block engine option that produced more horsepower than any Corvette that had come before it. Any Corvette, when ordered with RPO ZL1, came fitted with an all-aluminum 427 C.I. engine that featured a dry-sump oil system and which weight approximately 100 pounds less than the L88 engine. The ZL1 was a mid-year release for the 1969 Corvette and was actually developed to replace the legendary L88. In addition to the all-aluminum block, the engine featured stouter connecting rods and open-chamber heads.