One of the rarest Corvettes is the C3 Stingray fitted with the all-aluminum ZL1 engine. Only a handful of Vettes originally came equipped with the ZL1, but many racecars were later upgraded to include the ZL1 and produced upwards of 750 bhp. Like the L88 racing engine, Zora Duntov made the ZL1 available as a regular production option (RPO) but was rarely ordered because of its high price of $3,010 on top of the $1,032 L88 option.
