How do you improve on excellence? That was a situation that Grady Davis faced as 1962 wound to a close. Davis, then Gulf Oil's executive VP for research and development, owned a '62 Corvette which Dr. Dick Thompson was driving to win after A/Production win in the big SCCA races across the country, scoring 12 wins in 15 races.
Thanks to the work of Chevrolet's own R&D team, a new-second-generation Vette was in the works for 1963. That's what Davis chose to carry his (and Gulf Oil's) colors for the '63 season, a rolling test bed for Gulf's fuels and lubricants R&D program.
What Davis also chose for his new A/Production race car was the all-new RPO Z06 package, which added these race-grade parts to the production Sting Ray: Big drum-and-shoe brakes with vented backing plates, sintered metallic linings, finned aluminum drums, internal cooling fans and a dual-circuit master cylinder; special suspension front and rear, with stiffer springs, bigger front stabilizer bar and heavy-duty shocks; 36-gallon gas tank; and finned aluminum knock-off wheels. For power, there was the L84 fuel-injected 327, backed by a Borg-Warner T10 four-speed and Chevy's tried-and-true Positraction limited-slip differential.
With its first-of-the-line pedigree and impressive list of heavy-duty/racing equipment, Davis' racer was a historic Corvette even before it first rolled on to a race course. It was one of only 14 regular-production Corvettes whose serial numbers were specifically assigned to competition cars before Chevrolet announced RPO Z06's availability on January 1, 1963. It was also the first of two regular-production '63 Sting Rays assigned to Yenko Chevrolet, again specifically for competition. It was also the first Corvette to be prepared with advanced race technology developed especially for the RPO Z06 package, and later adapted to the prototype Corvette Grand Sports.
This car (Chassis No. 2227) and one other went to Davis, while five went to Mickey Thompson. All 14 of the "pre-assigned" Z06s went to top Corvette racers and race teams for the coming '63 season. When it came off the line at St. Louis Assembly in early-October 1962, Gulf Oil personnel picked the car up and drove it to Pittsburgh, where final race preparations were made. Then, it was shipped to Puerto Rico for the first-and, so far, the only-Puerto Rican Grand Prix. With Dr. Dick Thompson at the wheel, "Gulf One" (as it was now called, thanks to its backing and the competition No. 1 it wore) scored its first SCCA A/Production class win. One more race and win-in Marlboro, Maryland's "Refrigerator Bowl" in January 1963-and Gulf One was then prepared in accordance with FIA rules for action at Daytona and Sebring.
At Daytona, in the Daytona Continental sports-car race, Thompson piloted it to third place overall (behind two Ferrari GTOs) and first place in the GT3 class. Unfortunately, Gulf One DNF'd at the 12 Hours of Sebring due to transmission failure, after a strong qualifying effort and early-race run.
From then on, Davis entered Gulf One in big SCCA events across the country, just as he did the season before with their '62 Corvette, and-with Thompson at the wheel-it racked up class wins just like the '62 did. In particular, Gulf One took first place overall at the SCCA President's Cup race at Marlboro, Maryland, as well as A/P wins in SCCA races at Danville, Virginia, and Road America at Elkhart Lake, Wisconsin.
Davis, Thompson and Gulf One thrived that season despite two major obstacles. Carroll Shelby's Anglo-American hybrid, the AC Cobra, was appearing in greater numbers for 1963, powered by Ford's own small-block, while its chassis had four-wheel disc brakes-and the entire car weighed about 2/3 what a Z06 Corvette did. Plus, in late January, GM pulled the plug on all its factory-supported racing programs. Nonetheless, Gulf One was the most successful of the 14 "assigned" Z06s.