In 1969 Chevrolet let a handful of buyers order an all-aluminum, race-bred 427 that needed fuel no gas station actually sold — and it nearly doubled the price of the car it went into. Only 69 Camaros and 2 Corvettes ever left the factory with the ZL1 option. Read on for the dyno numbers, the drag strip runs that outran them, and why this engine’s window of availability was so brief.