Barely five years elapsed between the introduction of the '63 Sting Ray and the close of the C2 generation in the '67 model year, and during that time the Corvette stayed on a track of steady improvement that resulted in a world-class sports car. Things would be different in the Vette's third go-around. Not only was it the longest, at 15 years, but this Corvette generation had to weather a turbulent era that made it tough to hold on to its top-echelon status.
The Shark is Born
The sleek lines Larry Shinoda penned for the Mako Shark II concept car provided clear inspiration for the next iteration of the Corvette -- as well as the generation's "shark" nickname -- but turning concept into reality wasn't easy. The Mako's styling cues, particularly its tall fenders and upswept tail, made for a sexy show car, but not one that was easy to live with -- or see out of.
So Shinoda and his designers worked on making the Mako more livable, while Zora Arkus-Duntov, the Corvette's chief engineer, figured out how to fit the Vette's mechanicals within the new body envelope. Under the new skin the Corvette was essentially a carryover from the C2's later years -- same 98-inch wheelbase, chassis layout, and engine choices -- but the Mako Shark's front-end styling didn't allow for much airflow to the engine. The front air grilles were opened up, while an air dam was added under the car to help direct flow to the radiator. Front fender vents proved to be more than decoration and actually let hot air escape from the engine bay.
The previous IRS design was incorporated into the new car, but the front suspension was revised to help keep the tires planted under hard acceleration. The standard Rally wheels grew in width to 7 inches, allowing for big F70-15 meats at all four corners.
In addition to cutting down the Mako's tall fender In addition to cutting down the Mako's tall fender bulges, Shinoda's team also replaced the show car's dramatically styled boattail rear end with a vertical back window recessed between two buttresses. Initially the car had a lift-off, Targa-style roof, but without the reinforcement of a fixed panel, the body flexed too much. So instead, a strut was positioned between the windshield and the B-pillar arch, and removable roof sections flanked that strut, forming the Vette's T-tops.
The new Vette's interior was completely revised. The instrument panel now had a big speedometer and tach in front of the driver and a raft of other monitors in the center console. "Astro" ventilation -- which drew fresh air from the cowl and exhausted it via vents behind the back window -- was new, as was the removable back window.
As was the case in '67, engine options ranged from a 300hp 327 to the mighty L88. One big powertrain change was the addition of the three-speed Turbo-Hydramatic automatic transmission, which replaced the long-in-the-tooth Powerglide.
Reportedly, early customers weren't happy with the quality of the fiberglass bodywork on the new '68 Corvette, but that didn't stop Chevrolet from selling 28,566 of them, a significant lift from the 22,940 '67s sold. From a sales standpoint the Corvette would just get hotter and hotter, even if its performance parameters would soon suffer.
While the shark generation of Vettes lasted a long 15 years, the car's look was refreshed every five years, neatly breaking the C3s into three different sub-generations. The early C3s, the '68-'72 models, are distinguished by their chrome front and rear bumpers. Spotting the differences between those first five years gets a little trickier. The '68s, for example, did not wear the Stingray name, but the '69s did, and now the beast was spelled as one word, not two. Side exhausts were a one-year-only option in '69, as was bright trim for the fender louvers. The door buttons used in '68 were gone by '69, and the backup lights moved into the inboard taillights.
For the '70 model year (which was cut short by strikes and is often labeled '70-1/2), the front grilles and the fender louvers were redesigned with egg-crate patterns, the wheel openings were flared at the back, and the exhaust tips went from round to rectangular. That body style remained unchanged for the '71 and '72 model years.
There were more dramatic changes taking place underhood. The muscle-car era essentially peaked and then died between 1969 and 1972, and the Corvette's powertrain options mirrored those highs and lows. In '69 the base engine was enlarged from 327 to 350 cubic inches (though the 300hp rating remained the same); while at the other end of the engine spectrum, the all-aluminum, 427-inch ZL1 engine was added to the options list. Like the L88 the ZL1 was intended for racing use only, and like the L88 the ZL1's output was laughably underrated by GM brass at 430 hp.
Two new engines appeared for the '70-1/2 model year. Though the L88 and ZL1 were no longer available, the more garden-variety Mark IV big-block was stroked from 427 to 454 cubic inches, creating the LS5. Its 390hp rating was the same as the L36 427, but peak torque jumped from 460 lb-ft to 500. (A second optional big-block, the LS7, was mentioned in some dealer literature and featured in a couple of magazine road tests but never made it into production.)
A significant new small-block also came on the scene. Called the LT-1, it was an evolution of the 302ci small-block Chevy used for Trans-Am racing. With a solid-lifter cam, big valves in the heads, and 11:1 compression, the LT-1 pumped out 370 hp in the Corvette and 380 lb-ft of torque, and yet delivered those numbers in a package far lighter than big-inch motors offering similar output. Less weight over the nose, of course, meant a better-handling Vette.
Sadly, '70 would be the pinnacle powertrain year. Big-block buyers could still get a serious stump puller when the 425hp LS6 big-block was made available in Corvettes for '71, but otherwise, compression ratios were cut in a corporate-wide edict to reduce emissions. The LT-1 went from 350 hp to 330 in '71, the LS5 from 390 to 365.
And that was just the beginning. In the '72 model year it looked like every manufacturer's power numbers fell off a cliff, as the industry went from "gross" to "net" power ratings. The Vette's standard 300hp 350 was now rated at 200 hp, the LT-1 dropped to 255, and the LS5 to 270 hp.
Yet despite the decline in power, and despite the car's rising price -- a coupe cost more than $5,000 for the first time in '70 -- Corvette sales remained strong. And they would grow again with the '73's mid-cycle redesign.