In just a couple of months from now, you will have a reason to rejoice.
I’m not referring to the winter holidays. Nor am I talking about the ringing in of a new year. No, what I’m alluding to is something that I know will resonate deeply with you by virtue of the simple fact that you are reading my words right now.
For if you’re a fan of Street Muscle Magazine, it means you, like me, celebrate all things muscle and sports car related. And it so happens that 2023 carries with it a very special anniversary denoting the genesis of an automotive icon.
You see, next year will be the 70th anniversary of America’s sports car, the Chevrolet Corvette.
During the course of those seven decades, Chevrolet spawned eight generations of the ‘Vette, and some very rare, and very powerful models along the way that today’s enthusiasts are willing to spend big money to acquire.
There are the twenty 1967 L88 cars outfitted with the 427ci big-block, 4-speed manual, and Positraction rear that were produced. That’s certainly not very many. There are also the L89s of that same year. A mere 16 of those left the factory. Then there’s the 1969 ZL1, packing in excess of 500 horsepower. Only three, yes three, of those beasts ever roamed the streets.
But if you really want to use the word rare in the same sentence as the word Corvette, there’s only one model that fits the bill. It’s the 1971 Corvette ZR2 convertible. In an effort to celebrate the Corvette’s coming anniversary, this chapter of Rare Rides will be devoted to telling you all there is to know about that fabled unicorn.
So let’s get to it!
The third generation, or “C3” Corvette, of which the 1969 ZR2 was a variant, was first released in 1967 as a ’68 model. It was a radical departure from its forebears in terms of its aesthetics. Whereas the C1 and C2 ‘Vettes seemed to incorporate existing styling cues that defined their eras, the C3 was, in many ways, a progenitor of the designs for the decade to follow.
Work commenced on the third-generation car in 1964. Frank Winchell, then head of Chevrolet’s R&D department, Bill Mitchell, Styling Section Vice-President, and Zora Arkus-Duntov, director of high-performance Vehicles, agreed to come up with independent ideas as to what the C3 Corvette should be, and then work together to come up with a final design.
All three men were adamant that the current Corvette’s front engine layout should be scrapped but came up with different approaches to this.
Winchell’s concept was a rear-engine design with styling cues adopted from the Chevrolet Corvair and the Porsche 911. Duntov and Mitchell, however, opted for a mid-engine configuration based on the XP-755 Mako Shark show car that designer Larry Shinoda produced for the 1962 New York International Auto Show. Styling elements of both men’s concepts included that car’s pointed nose, a “double bubble” greenhouse, and a pointed tail that mirrored the front-end treatment.
In spite of the executive’s desire to move away from a front-engine configuration, budgetary concerns, weight distribution issues, and a dearth of mid- and rear-engine parts compatibility ultimately killed the idea. The C3 Corvette would remain a front-engined car.
Bill Mitchell once again handed the design reigns to Larry Shinoda to come up with a concept. The result would be given the moniker Mako Shark II.
By 1965, a non-running model, internally known as the XP-830, was built and shown to the public, again at the New York International Auto Show. Said to have been inspired by “creatures of the deep,” it featured such oddities as a blue-fading-to-gray paint scheme, a retractable rear spoiler, a front-hinged clip and hood, and a push-button-activated retracting roof. Reaction to the Mako Shark II was tremendous, giving Bill Mitchell and Frank Winchell a clear mandate for the direction of their new car.
Work on a viable production version of the Mako Shark II began forthwith, with a target release date of 1966 as a 1967 model.
To save money, the C2’s chassis was reused and adapted to the C3 with minimal changes. The wheelbase remained unchanged at 98 inches, but the overall length of the new car would be slightly larger, at 182.1 inches versus the C2’s 179.3.
The Mako Shark II’s body was tamed for production, but the most visually striking elements – most notably the long hood/short deck proportions, the oversized fender hips, and the ducktail rear – remained. The bodywork, in long-held Corvette tradition, was once again constructed of fiberglass for weight savings, but some brand-new styling adornments made their introduction.
These included pop-up headlights, windshield wipers hidden under a vacuum-operated panel, push-button door handles, and functional front fender vents for engine cooling.
Under the hood, the C2’s engine roster was retained. It included the standard, 300 horsepower 327 cubic-inch small-block V8, a 350 horsepower version of the same motor, and three big block options: the 390 horsepower, L36 version of the 427, the 400 horsepower L68, and the monstrous, 435 horsepower L71. The latter engine could be had with the L88 and L89 aluminum head packages for maximum grunt and lighter weight.
Transmitting the power was a standard three-speed manual, an optional four-speed Muncie unit, and the brand-new, Turbo Hydramatic three-speed slushbox.
Putting the power to the ground came from a huge choice of final drive ratios ranging from 3.36:1 to 4.56:1, depending on engine and tranny configuration. Positraction was a popular option.
Suspension consisted of independent upper and lower A-arms with coil springs, tubular hydraulic shock absorbers, and an anti-roll bar up front, and the C2’s set up in the rear, composed of independent leaf springs, struts, trailing arms, and tubular hydraulic shocks.
Four-wheel, 11.75-inch disc brakes were standard, as were 7×15-inch wheels and low-profile F70x15 tires.
Inside, the C3 was a bit more cramped than its predecessor, though it had many amenities. A comprehensive gauge package consisting of a tachometer and speedometer pods in the main binnacle and ancillary gauges at the top of the standard console gave the driver all the info he or she needed. An “Astro Ventilation” system routed fresh air from the cowl and out through grills on the deck behind the rear window.
Additional interior features for the C3 included an electric rear-window defroster, a speed warning indicator, AM/FM stereo radio, and a high-tech, fiber-optic light monitoring system.
Despite Chevrolet going all out in the design of their new sports car, there was a serious problem with the initial pre-production models: dangerous front-end lift under hard acceleration was revealed during testing. This was primarily caused by the shape of the C3’s nose, prompting Duntov, in a moment of candor, to state that the new car “had the aerodynamics of a bad airplane.”
Rectifying this required bodywork vents to be engineered and spring rates to be stiffened. Accomplishing these tasks ultimately meant that the C3 would not meet its release date, and would, in fact, be postponed for a whole year.
Upon the C3’s release as a 1968 model, much of the excitement generated by the Mako Shark II concept faded in the face of even more issues. Reviews by major automotive publications elucidated many shortcomings.
Amongst them were a harsh ride caused by the increase in spring rates, poor interior ergonomics involving ingress and egress as well as the fixed seat back angle, occasionally non-functioning windshield wipers, a noisy cockpit, and most of all, substandard fit and finish. So bad were these flaws that one magazine returned their test car to Chevrolet, calling it “unfit to road test.”
In spite of this, the public was largely enthused by the fresh, future-forward styling and the car’s excellent performance, regardless of engine/tranny choice. In just the first year, 28,566 C3s were sold, a Corvette record and some 5,000 units up on the previous year.
For 1969, major design changes were few, as Chevrolet concentrated mostly on rectifying the issues with the first-year car. Some interior shoulder space was afforded by narrowing the thickness of the door panels, and getting in and out of the car was made easier for the driver by way of a smaller diameter steering wheel. Outside, the over-engineered door handles and wiper system were redesigned for smoother operation.
Most importantly, the C3’s frame was heavily stiffened to reduce body shake, and 8-inch-wide wheels with taller sidewall tires were made standard so as to give a slightly more compliant ride.
Engine options were given some love as well. The famed small-block was stroked about a 1/4-inch, which boosted displacement from 327 to 350 cubic inches with 300 and 350 horsepower versions being offered. Most notable though, was the ZL1 option which lumped an all-aluminum version of the L88 big-block along with dry-sump lubrication and other niceties to make for a beast of a Corvette.
1970 was largely a carryover year, with only some minor tweaks to the interior and exterior and the planned replacement of the L88 with the massive 454 cubic-inch LS7 big-block. Sadly, owing to Federal compliance issues, no cars were ever built with this package.
This brings us to 1971. Owing largely to impending Federal mandates aimed at reducing exhaust emissions, General Motors president, Edward Cole, decreed that all GM cars would, starting in 1971, be capable of running on 91-octane, lead-free gasoline. This necessitated a reduction in engine compression, which in turn reduced the output of all motors across the board. Combined with rising insurance costs, these emissions requirements would have the effect of ringing the death knell for large-displacement, high-power engines in the future.
With all the impact of a raised middle finger, Chevy chose this moment to register their dissent to these changes by releasing a monster of a lump to act as a swan song to the golden era of power – the 454 cubic-inch LS6.
Essentially a slightly detuned version of the previous year’s stillborn LS7, the LS6 was developed specifically to run on low- or non-leaded lower-octane fuel.
Sporting a 4.251 x 4.00-inch bore and stroke and a 9.0:1 compression ratio, the LS6 featured open-chamber aluminum heads, modestly domed pistons, a Holley R4555A four-barrel carb, and an aluminum intake. Output was a sarcastically underrated 425 horsepower at 5,600 rpm, and 475 lb-ft of twist at 4,000 rpm. Actual output was well in excess of 500 horsepower.
A recipient of this beastly powerplant would be an equally audacious new model variant known as the ZR2.
Considered a dedicated vehicle (read as a car designed specifically to dominate drag strips, yet be fully street legal), the ZR2 Special Purpose Package included the LS6 plus a bevy of performance upgrades.
These included a cutting-edge, transistorized ignition, a close-ratio, four-speed Muncie M22 “rock-crusher” transmission, a dual-plate clutch, an F41 heavy-duty suspension package with special springs, shock absorbers, spindle-strut shafts, and front and rear stabilizer bars, the J56 dual-pin power brakes, and a cooling system with an aluminum radiator and fan shroud delete.
When outfitted with the ZR2 package, buyers were unable to add many of the Corvette’s more sumptuous amenities, such as air conditioning, power steering, wheel covers, power windows, rear window defroster, alarm system, and radio. It was clear that Chevy meant this to be a lightweight stripper of a dragster.
The ZR2 package added $1,747 to the $5,496 base price of a Corvette, putting it in the range of many German and Italian sports cars, and making it nearly twice as expensive as a nicely appointed Chevelle.
For the money though, you received a car genuinely capable of destroying many factory street-legal production cars. A road test by one car magazine pegged the ZR2’s straight-line performance at 5.1 seconds to 60 mph and a quarter-mile pass in 13.1 seconds at 104.65 mph. Heady performance, indeed.
Because of its very dear price, special purpose, and lack of amenities, the ZR2 was exceedingly rare, with only ten people in the world opting to purchase one.
This number paled however in comparison to the number of ZR2 convertibles that were built in 1971.
Only two – one painted in Ontario Orange, and one wearing Brands Hatch Green – ever left the factory, making the ZR2 convertible the rarest production Corvette ever made, and the last high-performance, big-displacement model until modern times.
Today, the 1971 Chevrolet Corvette ZR2 convertible is one of the most coveted cars of the era. In fact, the green ragtop changed hands at Mecum’s 2022 Indianapolis auction for an astonishing $962,500 plus commission, making it truly one of the world’s great Rare Rides.