Chevrolet built 199 Corvette Z06s for 1963, and only 63 of them got the Z06 big tank. That oversized fuel tank held about 36 gallons, against roughly 20 in a regular Corvette. For a racer, it meant fewer stops in a long endurance race.

The Z06 was not a separate model. Instead, it was an option package for the brand-new Sting Ray, aimed squarely at people who planned to go racing. Chevrolet made it hard to order by accident, and that is part of why so few exist.

Here is what the package included, what it cost and why the big-tank cars stand apart. The figures come from CorvSport, Classic Industries, Corvettes.nl and Motorious, all linked below.

What the 1963 Z06 package included

Zora Arkus-Duntov, the Corvette’s lead engineer, developed the Z06 to make the split-window coupe better on a race track. That is how CorvSport’s model guide describes it. Most of the package went into the brakes and suspension.

The brakes were still drums; however, they were heavily upgraded. CorvSport lists sintered-metal linings, a dual-circuit master cylinder and a vacuum brake booster. In addition, Classic Industries lists finned drums, cooling ducts and vented backing plates.

Underneath, the suspension also got much stiffer. CorvSport gives the front stabilizer bar as 24mm thick. It also says the springs and shocks roughly doubled the stiffness of the standard parts. Similarly, Classic Industries calls the front bar 20% stiffer and the springs and shocks nearly twice as stiff.

A fuel-injected 327 came first

Buyers could not add the Z06 to just any Corvette. According to CorvSport, they first had to order a fuel-injected coupe with the 360-hp L84 engine, a four-speed manual and a Positraction rear axle. Duntov set that rule so the package went to track-minded buyers, the guide says.

For reference, the L84 was a 327-cubic-inch small-block V8. Classic Industries gives its compression as 11.25:1 and names the gearbox as a Muncie four-speed. Meanwhile, Corvettes.nl notes that Rochester fuel injection fed it.

The ordering rule also had a background. CorvSport explains that the Automobile Manufacturers Association strongly opposed factory-backed racing in the late 1950s. As a result, GM barred its divisions from building track-ready cars. So a racer had to assemble one from the order form instead.

Why the Z06 big tank mattered

The tank was the package’s key racing part, according to CorvSport. It held 36.5 gallons in CorvSport’s figures and at Corvettes.nl. However, Classic Industries and Motorious both call it a 36-gallon tank. Either way, it was close to double the standard tank, which CorvSport puts at 20 gallons.

Corvettes.nl says the tank was meant for long races such as Sebring and Daytona. Classic Industries describes it as fiberglass and lists it as RPO N03, at a cost of $202. Because of the Z06 big tank, these cars became known as “big tank” or “tanker” Corvettes, CorvSport says.

At first, the big tank came only on the coupe. CorvSport says it would not fit under the convertible. Later, Chevrolet reworked the convertible to take it, the guide says. Even so, CorvSport says it is believed that Chevrolet built only one Z06 convertible. By contrast, a 2017 Sports Car Market profile by John L. Stein says no convertible ever got the big tank.

The package also changed later on. Corvettes.nl says Chevrolet lowered the Z06 price and dropped the big tank from the package. Sports Car Market gives the numbers: the option started at $1,818.45 on coupes, then fell to $1,293.95 later in the year as it opened up to convertibles.

Meanwhile, the tank lived on by itself. CorvSport says it became a separate option, N03. According to Sports Car Market, it cost $202.30 as a stand-alone coupe option and stayed on the list through 1967. Over that five-year run of the mid-year Sting Ray, the magazine counts only 210 big-tank coupes in all.

What the Z06 cost in 1963

The Z06 option cost $1,818.45, according to both CorvSport and Corvettes.nl. That was a large sum next to the price of the car itself.

The base price depends on the source. Corvettes.nl and Classic Industries both give $4,252 for the 1963 coupe, and Classic Industries says the Z06 added nearly 43%. By contrast, CorvSport lists a $4,037 base coupe and says the option added nearly 50%.

From the race track to the auction block

The Z06 went racing right away. Corvettes.nl says the cars made their debut at the LA Times Three-Hour Invitational in October 1962. Dave MacDonald, Jerry Grant and Bob Bondurant drove them there.

Later accounts fill in more. Sports Car Market covers the rest of that weekend at Riverside International Raceway. Four Corvettes ran in the support race for production sports cars, and they were driven out from the St. Louis assembly plant. Bondurant drove the Washburn Chevrolet car. In the end, Doug Hooper won in a Z06 entered by Mickey Thompson, which gave the Sting Ray its first victory.

Afterward, most Z06s went to racers, and many took heavy track damage over the years. That is why survivors are scarce today, CorvSport says. The option itself did not return for 1964. According to Sports Car Market, the Z06 name came back in 2001 on a C5 hardtop.

Those survivors now trade at serious money. For example, CorvSport reports that a 1963 Z06 tanker sold for $450,000 at Mecum’s 2016 Houston auction.

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This article was created with the help of AI and was reviewed and edited by Fast Lane Only editors before publication.