I just learned the origin of the Z06 is “Zora’s Option 6.”

Corvette’s patron saint (and after 1967, chief engineer) Zora Arkus-Duntov following the arrival of the (Ford) Shelby Cobras in 1962, understood that Corvette owners needed competition parts to safeguard their Sports Car Club of America’s (SCCA) A-Production turf.

Avoided alerting GM’s upper management but still drew potential competitors, with a new-for-1963 racing package codenamed “Zora’s Option 6” listed as a regular-production-option.

https://www.hagerty.com/media/car-profiles/six-decade-corvette-z06-odyssey/

In October 1962, 3 Z06s faced off against one of the first Shelby Cobras at the Los Angeles Times three-hour invitational road race staged in Riverside, 

The Cobra driven by Bill Krause was competitively quick but DNFed after 90 minutes with a failed rear hub carrier. 

The Corvette fielded by Mickey Thompson and driven by Doug Hooper—beat a Porsche 356 to seize an overall victory.

So shortly after, Chevrolet Engineering purchased one of the early Shelby Cobras, a white car acquired for Arkus-Duntov’s evaluation. 

The Cobra’s 900-pound weight advantage inspired his 1963 Corvette Grand Sport, a hoped-for 100-car run of ultra-light sports cars which GM nipped in the bud after only five were built.

Wrap your mind around the fact that a Cobra was owned by Chevy Engineering.... led to the Vette GS. I'd love to know what happened to the Cobra after Chevy parted with it

https://www.facebook.com/Petersen.Photo.Archive/photos/1962-la-times-grand-prix-riverside-3-hour-endurance-race-the-first-major-event-f/860543280643619/