Corvette History Part 4: The C3 (1968-1973)

Hot on the heels of the iconic C2 Sting Ray comes the longest-running Corvette generation, racing through 14 years of production.

The Corvette built an impressive reputation for itself by 1967, occupying the garages of famed dilettantes and racers alike. By now, the Corvette represented Chevy’s magnum opus. As such, no expense was spared in developing the third generation. The Muscle Era dominated the timeframe, with manufacturers competing in their own Cold War on and off the track. As vehicle design grew bolder and harder, the C2 Corvette’s slim lines retained the car’s unique presence on American roads.

However, the times were changing, as were the collective desires of contemporary gearheads. With the advent of powerful big-blocks and better running gears came the requirement for a purpose-built vehicle, a Corvette designed from the outset with muscle in mind. Chevrolet charged the combination of the classic GT lines with the biting impact of a muscle car to the perfect men for the job: Zora Arkus-Duntov and Bill Mitchell. So without further delay, let’s explore the history behind the final Corvette attached to their names: the C3 Stingray.

Adding a Little Extra Muscle

The year’s 1964. Bill Mitchell and Larry Shinoda’s design for the C2 Corvette created an American icon. The striking visuals of the Sting Ray created a swathe of positive feedback both on and off the track. However, the Muscle Era slowly crept into view. Big blocks loomed on the horizon, and vehicles such as the famous Le Mans GTO debuted. The Corvette itself had no trouble competing against the rising Ponycar market. But the radical new styles of the day certainly left a mark on the GM design team.

So for the rest of the year, Mitchell’s design team penned what became the next evolution in Corvette concepts: the Mako Shark II. Debuting at the 1964/5 New York World’s Fair, the car represented Mitchell’s idealized future for the Corvette. The Mako Shark II featured the same paint scheme as the original Mako Shark I, and externally appeared as a more hard-edged, sweeping design.

Though undoubtedly very similar, the Mako Shark II incorporated one critical element into its initial design: a 427 engine right out the gate. A non-running show car toured Europe, touted as the next evolution in Corvette design philosophy. A grand tourer designed expressly with a big-block engine in mind while retaining the flowing silhouette and handling characteristics. Meanwhile, the C2 gained the same engine, with press and drivers alike lauding its power and reliability.

Mako Shark II’s internal designation was XP-830. In 1969, the Design Center updated its design, re-christening it the Manta Ray. It currently resides in this configuration in GM’s Heritage Collection.

After numerous showings of the Shark II as well as the reception of the 427, management knew without a doubt as to where the Corvette’s headed. Initial production timelines placed the car in showrooms as quickly as 18 months. But due to redesigns and teething issues, the Corvette ultimately took twice as long to see the light of day. By the time the first C3 left the floor, the car deviated significantly from the Shark II in terms of design. However, the overall shape of the car remained the same. As, of course, did its big block heart.

Grand Tourer Meets Muscle Car: A Match Made in Heaven

In spite of the various design changes, the C3 Corvette struck a particularly resonant chord with the public. The Stingray (now one word), like most muscle cars, featured an extensive options list, including several configurations of small and big-block V8s. And, of course, a couple options not included in the brochure. Each combination led to wildly varying handling profiles. The lighter 327 provided excellent balance and weight distribution, while the 427 created a somewhat violent torque-driven monster. The underpinnings largely featured holdovers from the C2, such as suspension and brakes. As such, early C3s remained relatively simplistic, closer to being true muscle cars than any Corvette in the generation. However, this didn’t act to the C3’s detriment, as approximately half of sales came with big-blocks. By the time 1969 rolled around, the Corvette even developed significant overseas popularity, competing in European racing series such as Le Mans.

C3 Corvettes competed in Le Mans from 1969-1976 consecutively. In this timeframe, the top finish was 12th, for the French Greder Racing Team. (Image source: Flickr)

1969 provided in some ways the apex of the muscle-era Corvette. This year saw the first Corvette to feature the ubiquitous 350 small-block, Chevrolet’s final development of the 4-inch bore family. We’ll talk more about this engine in a separate piece. But suffice it to say, the 350 Small Block Chevy became a household name for a reason. For 1969, the base engine produced 300 horsepower with an optional L46 package at 350 horsepower. Or you could, of course, opt for a number of 427s, ranging from the 390-hp L36 to the infamous aluminum-block ZL1 package. Good luck getting your hands on one of those, however – only two C3 ZL1s were ever produced.

Aside from the breadth of engines, the car featured a plethora of configurations ranging from Spartan to full-on GT. The latter created the most quintessential grand-touring experience, with Chevrolet marketing their driving style as “enthusiastic, comfortable and convenient.” The Corvette solidified this experience through both mechanical and comfort-based options such as Posi (so popular it might as well be standard), power steering and brakes, and the all-important A/C. This led to the C3 being in many ways a hybrid between a true sports car and a savage muscle car. Coupled with its unique design, this philosophy created a very specific niche that the Corvette effectively monopolized throughout the late ‘60s and early ‘70s.

The Corvette that Closed the Muscle Era

By 1970, muscle cars saturated the US enthusiast market. As such, this model year saw the Corvette drawing even more design cues from these bold, wide-bodied vehicles. The Stingray now received bold fender flares, squared-off exhaust, and a minor facelift with new grille and vents. A wide-ratio 4-speed became standard, with an optional M22 “Rock Crusher” heavy-duty 4-speed and the Turbo Hydra-Matic remaining alongside. Meanwhile the 350 grew extra legs in the form of the LT-1, producing 370 horsepower. And much like the rest of the car, the big block grew in size as well, now the classic 454. This engine found its way into the Corvette in the form of the LS5 and LS7, producing 390 and 460 horsepower respectively. However, due to a relatively short model year as well as no orders, factory 1970 LS7s remain a disputed topic, with sources ranging from one or two existing to none at all. Despite this, Chevrolet did offer the LS7 as a crate engine.

In 1971, the 454 grew in popularity, with GM offering the 425-hp LS6 in place of the failed LS7. Externally, however, the 1971 Corvette remained essentially unchanged, wearing the same exterior and interior. However, more substantially, 1971 marked Corvette’s only year of publishing both gross and SAE net horsepower ratings. The politics behind this decision reach back a ways, but here’s the simple explanation. Gross horsepower is what most manufacturers used in brochures. It’s essentially horsepower on a test stand without any parasitic load. Net horsepower, however, indicates the actual horsepower of the engine in the car with accessories. So for example, the LS6’s gross-hp rating indicates 425, while SAE net is only 325 hp. By 1972, gross horsepower disappeared completely – all ratings from now on are in SAE net only.

Due to smog regulations, 1972 Corvettes sold in California weren’t available with the LS5 270-hp 454.

1972 saw the finale of the Muscle Era Corvette, distinctly marked with the last usage of chrome bumpers. We also saw the final usage of the LT1, this time rated at 255-hp. Not mentioned yet was the ZR-1 package, built around the small block. This package essentially equipped a Corvette with all the trimmings of a proper race car in terms of running gear. Coupled with the LT-1, this created arguably the most balanced, competitive C3 Corvette ever. However, ZR-1s are appropriately extremely rare, with only 53 produced between 1970-1972.

Entering a New Era

We’re all familiar with what happened in 1973. However, the Corvette got a bit of a leg-up with its transformation away from the Muscle Era. The 1973 model year saw a marked tonal shift in the car’s philosophy towards being a purist sports car first and muscle car second. And it plays up the sports enthusiast crowd more than ever before. In the 1973 brochure, for example, it states, “The Vette is that kind of car. The kind that brings out the driver in you. And it does that very well, thank you.” In a sense, the chrome front bumper deletion’s a regression to the Mako Shark II, which itself featured no such prominent bumpers. And you now had other creature comforts like radial tires standard, further solidifying its status as a more premium vehicle. Despite this, the Corvette remained one of the most affordable ways to go fast, priced at $5,398.50 to start.

Ultimately, many muscle cars met their fates at the hands of the Malaise Era. Whether dropped entirely or transformed into machines virtually unrecognizable from their 1960s counterparts, the Oil Crisis struck these vehicles without discrimination. However, the Corvette remained one of the final holdouts, thanks largely to this sports-car-first philosophy. Next time, we’ll continue the C3’s story throughout this pivotal historical moment right up to the last one rolling off the line in 1982.

Brochures used: 1968-1973 Corvette

Mako Shark II images from: GM Heritage Center

.

‎