The introduction of the 2023 Z06 Corvette celebrates the 60-year legacy of one of the marque’s most successful options. This high-performance package was first developed by Zora Arkus-Duntov and his team when GM ruled that racing was too dangerous for a corporation to support. In June of 1957, the company signed a binding AMA (American Manufacturing Association) agreement that forbade corporate racing activities. Zora’s solution was to develop a workaround that enabled his team to develop high-performance Corvette packages. GM offered them to customers so they could race their Corvettes. These upgrades could be purchased by ordering a car with the parts installed at the factory, or buying and installing them from your local dealer. It was a silly game that only GM engineers had to endure, since Ford and Chrysler soon ignored this AMA ban completely.
With the advent of the totally redesigned 1963 Sting Ray, Zora’s team assembled a new performance option during the car’s development. It was called the Special Equipment Package and could be ordered with the dealer code Z06. It included a handful of stand-alone options, such as the 360-hp fuel-injected L84 V-8 engine, a 36.5-gallon fiberglass fuel tank, a four-speed close-ratio manual transmission, and a Positraction rearend. The L84 was nearly identical to the 340-hp Carter AFB-equipped L76, but with the obvious distinction of having Rochester mechanical fuel injection, along with slightly different cast-iron exhaust manifolds. Both engines came equipped with the same camshaft and forged-aluminum pistons that were domed to facilitate an 11.25:1 compression ratio that bumped the power rating up to 360 hp. The engine was dressed up with a pair of veined aluminum rocker covers. The top of the intake plenum on the fuel-injected engine matched the look of the rocker covers. Beyond the regular options, Z06 also included some very special components, most notably in the braking department. While power brakes and sintered metallic linings were available as separate options, the Z06 package featured oversized, finned steel brake drums with internal fans and a unique dual-circuit, vacuum-boosted master cylinder. In addition, “elephant ear” brake-cooling ducts directed under-car air to the front binders. The multi-segment brake shoes themselves were lined with a material known as Cerametalix, a different compound than was used with the regular sintered-lining option.
Z06 buyers also found themselves in possession of unique, heavy-duty shocks and firmer springs. While all 1963 Corvettes were equipped with a front anti-roll bar, Z06s received a 20-percent larger bar that complemented the unequal length A-arms and coil springs on the front end. Between the suspension and brake upgrades, Chevrolet created a car that could compete with Europe’s best on the road courses, while the potent fuelie engine helped it reach into the 14s on the quarter-mile. It was originally priced as a $1,818.24 option, only available on coupes. Later in the production cycle, Chevrolet removed the endurance-racing fuel tank as mandatory on the Z06 list (though still kept it as a separate option), which knocked the option price down to $1,293.35. GM also made the Z06 available to convertible buyers, but only one of the 199 Z06s made for 1963 was a roadster. Ultimately, Chevrolet built just 78 Z06 coupes with the massive 36 gallon fuel tank.
The Z06 was ready to race from the factory. This was confirmed when three of the first cars completed off the assembly line were driven from St. Louis to Mickey Thompson’s Los Angeles shop. The trip was used to break the new cars in. After some minimal race prep, four cars (a fourth one was trucked to L.A.) were entered in the October 14, 1962, Los Angeles Times Grand Prix at Riverside. Competition was fierce and the new Corvettes were untested, particularly against the new Cobra, which was a 1,000 lbs. lighter. The Cobras and most of the Corvettes suffered mechanical maladies, but Doug Hooper emerged victorious in a Z06, making the car a winner its first time out. Even though only 199 cars were built for 1963, these cars went on to accrue multiple racing victories.
There was a 38-year gap before the Z06 option was revived and offered again. This occurred with the 2001 model year release of the Z06, which was available only with a six-speed manual transmission. It was upgraded with a 385-hp LS6 engine and sold as a complete car filled with the latest special performance options. The base Z06 was priced at $47,500 and 5,773 were purchased. This option was discontinued at the end of 2004 with the introduction of the redesigned C6. The Z06 reemerged in 2006, again with a six-speed manual as the only transmission option. It was powered by the 505-hp 427ci LS7 engine, and featured an all-aluminum frame. This new model was priced at $65,800 and 6,272 were sold. It continued to the end of C6 production in 2013. The C7 was introduced in 2014 and the Z06 version became available to customers the following year. This new model was available with manual or automatic transmission, and a coupe or convertible. Its LT4 supercharged engine produced 650 hp and 650 ft-lb of torque. The Z06 coupe’s base price was $78,995, and the convertible cost $83,995. A total of 8,653 were sold in 2015 and the model continued to the end of C7 production in 2019.
Zora Duntov’s dream Corvette became a reality when the mid-engine C8 was introduced in 2020. This radically different Corvette design is now completing its third year of production. For 2023 the Z06 has returned as a shrieking 8,600-rpm banshee of a normally aspirated supercar. Regular C8 production began in early May, but due to supplier delays Z06 production is forecast to begin later in 2022. Those of us who have seen and heard this new offering can assure you it will be well worth the wait.
The History of the Corvette Z06 in Pictures
Zora Arkus-Duntov (1909-1996) joined General Motors May 1, 1953 and was a brash non-conforming executive. By 1956, he had transformed the original 1953 Motorama Corvette into a “real McCoy” sports car that was winning races and setting records. Zora always wanted to build a rear-engine Corvette and the success of the C8 confirms his vision.
Zora and his team built this 1957 Corvette SS to compete in international sports car racing. It debuted at the 1957 12 Hours of Sebring but was withdrawn after 23 laps for suspension failure. It never raced again after GM signed an AMA racing ban in June 1957 that forbade corporations from participating in automobile racing.
GM designer Bill Mitchell bought the SS test mule chassis for $1 and had his styling team, including Pete Brock (pictured), develop this stunning Sting Ray body to cover the former SS chassis. Because the company was not racing, Mitchell built the car in a rented garage near the company’s Tech Center. He hired Dr. Dick Thompson to race the car in 1960 and won the SCCA C-Modified championship with it. Because of the corporate racing ban, Zora and his team were forbidden to work on it.
Mitchell’s Sting Ray race car was a hit with the public. His design was translated into a record-breaking production car named Sting Ray, of which 21,513 were sold. Zora convinced Chevrolet Chief Engineer Ed Cole to let his team build a “Special Performance Equipment” option named “Z06” for amateur racers. This example looks like a standard 1963 Sting Ray, but it is one of 199 built with the Z06 option.
Photo: Dave Friedman
Stiff Competition From Ford
As the new Sting Ray was being readied for production, Zora prepared four Z06 Corvette coupes to compete against Ford’s new 2,019-pound Shelby Cobra at Riverside Raceway in California. Four Z06’s were driven from the St. Louis plant to Riverside to compete against the Ford. This Z06 was the first built and was driven by Dave McDonald at the Riverside Race. It retired after leading when it lost a wheel bearing. Doug Hooper won the race in another Z06. The Cobra was 1,200 pounds lighter than the Corvette and powered by 260-hp, 260ci Ford engine. It had a base price of $5,995, sprinted from zero to 60 in 4.2 seconds, and covered the quarter-mile in 13.8 at 112 mph with a top speed of 153 mph.
Photo: Dave Friedman
In early 1963, the Cobras underwent a rapid development program. These three team cars were well-prepared and driven by the top drivers of the era. The Corvette Z06 was struggling to beat them.
This Gulf #1 was one of a pair of Z06 Corvettes ordered by Grady David of Gulf Oil. It was filled with racing options not available to the public. It won multiple races against the Cobras and was driven by Dr. Dick Thompson and Don Yenko.
Unlike race cars today, the Gulf #1 Z06 had a showroom-stock interior. Note the lack of window regulators; side windows were held in place with Velcro strips. Reducing weight continued to be a goal with Z06 competitors.
Every Z06 was equipped with this L84 fuel-injected engine. It produced 360 hp from 327ci, and after proper race-tuning, power levels increased well above this number. The Z06 option was discontinued at the end of 1963, but continued to be improved through racing. Zora was concerned about how the Z06 was struggling to beat the Cobras, so his team began building a 2,000-pound Cobra-beater called the Grand Sport.
This is Grand Sport #004, owned by the Revs Institute in Naples, Florida. Five Grand Sports were built, and three attended the Nassau Speed Weeks in November, 1963. The 2,000-pound, 377ci, 485-hp lightweight Corvettes stomped Shelby’s Cobra’s during the weekend event. Corvette team engineers (including Zora) took vacations to support the Grand Sport team. All five Grand Sport cars remain in private collections.
Z06 Corvette Reborn
After a long hiatus, the Z06 returned to the Corvette lineup in 2001. It mimicked the lightweight design of the 1999/2000 fixed-roof coupe (3,015 pounds) and was packed with performance equipment designed for racers. A total of 5,753 were sold, all powered by a 385-hp LS6 engine.
The Z06 Corvette was a perfect race car for drivers campaigning on a lower budget in a racing series like the now defunct SCCA SpeedVision GT series.
Amateur racers successfully raced the Z06 for many years in the SCCA T-1 category. John Heinricy, shown here, won five T-1 championships driving Phoenix-prepared C5 Z06 Corvettes.
In 1997, GM contracted the Pratt & Miller racing organization to develop a factory-based GT racing program around the C5 Corvette. By 2001, the program matured and was highlighted by winning the GTS class and finishing 8th overall. Many lessons learned from this program were incorporated into the development of the next-generation Z06.
GLPK racing in Holland purchased this ex-Pratt & Miller C5-R and successfully raced it in Europe.
Sixth-Generation Corvette Gets a Z06 Package
In 2005, the Bowling Green Assembly Plant began building the C6 Z06. It was powered by a 505-hp 427ci LS7 engine, and was not offered with an automatic transmission.
Pratt & Miller’s C6-R race car was closely patterned after the production street car. C6 chassis #001 is shown sweeping through Sebring’s Turn 10 on its way to a class victory at the 2005 12-Hour Enduro.
At the NCM Birthday Bash in April of 2005, Chief Engineer David Hill introduced one of the first 2006 Z06 coupes built.
The large crowd was very excited to learn about this lightweight and powerful new Corvette. Chief Engineer Hill provided a detailed analysis of what steps were taken to reduce the car’s weight without compromising strength.
In December 2005, GM authorized Callaway Competition in Leingarten, Germany, to build and race a Z06.R GT3 Corvette. A total of six cars were built to compete in the new FIA GT3 International Racing series.
The first Z06.R debuted at the FIA Annual Conference in Monaco, and at the Paul Ricard race track in France. Teams began racing them at the season’s first race at Silverstone, England.
A spirited battle between the Mercedes Gullwing GT3 coupe and Callaway Competitions Z06.R saw the ADAC Drivers Championship being awarded to Daniel Keilwitz and Diego Alessi. In all, Callaway Competitions C6 Z06.R GT3’s won three Drivers’ Championships, multiple Team Championships, and many overall victories. The heart of the Z06 beat strong in this amazing GT3 Corvette.
GLPK campaigned two Pratt & Miller C6.R ex-factory race cars. They won the 24 Hours of Spa twice and competed in the FIA GT1 World Championship series, and were always a threat for overall victory.
C7 Z06: Raising the Bar
A startling new redesign of the seventh generation Corvette, unveiled in 2013, paved the way for another rebirth of the Z06 option in 2015. Packed with a 650-hp supercharged LT4 engine, this new design raised the bar for the Z06 option.
Once again, Pratt & Miller closely patterned their GTLM race car after the street car. The storied team won multiple races and championships with this C7.R race car.
Callaway Competition built this ultra-high-tech C7 GT3 Corvette, which was used by Jules Gounon to win the ADAC GT Masters Championship In 2017.
All of the world’s best sports cars competed against Jules and his Corvette, but to no avail. Race after race, the Corvette continued to accumulate enough championship points to secure the drivers’ and team championships. Callaway Competition stopped competing at the end of the 2021 season.
This Pratt & Miller C7.R is now being raced by a private collector, and continues its winning ways.
The Best Z06 Yet?
Now we begin a new Z06 era, with the introduction of the 2023 LT6-powered C8. The new car is powered by a high-revving, flat-plane-crank, normally aspirated 5.5-liter V-8 with an 8600-rpm redline and an output of 670 hp. Production should begin soon.
The Pratt & Miller C8.R has been racing successfully since 2020 in the GTLM category. For 2022, the GTLM class was abolished and replaced with GTD Pro/Am. This C8.R competes in the GTD Pro class.
The C8.Rs utilize a gray-and-yellow livery that helps identify the team cars during competition. A GT3 version of this car will become available to private teams in time for the 2024 racing season.
After 60 years, the Z06 legacy continues to thrive with the latest version of this world-beating car, the 2023 C8 Z06.
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