The
third generation Corvette, patterned after the Mako Shark II concept
car, was introduced for the 1968 model year and lasted until 1982. C3
coupes featured the first use of T-top removable roof panels and were
sold in record numbers despite changes due to EPA regulations and the
gas crisis of the 1970s. It introduced monikers that were later revived,
such as LT-1, ZR-1, and Collector Edition. The Corvette's 25th
anniversary was celebrated in 1978 with a two-tone Silver Anniversary
Edition and an Indy Pace Car replica edition. It was the first time that
a Corvette was used as a Pace Car for the Indianapolis 500.
Engines and chassis components
were mostly carried over from the C2, but the body and interior were
new. The 350 cu in (5.7 L) engine replaced the 327 cu in (5.36 L) as the
base engine in 1969, but power remained at 300 bhp (224 kW). 1969 was
the only year for a C3 to optionally offer either a factory installed
side exhaust, or the all-aluminum ZL1 427 cu in (7.00 L); The special
big-block engine was listed at 430-hp (320 kW), but was reported to
produce 550 horsepower (410 kW) and propelled a ZL1 through the 1/4 mile
in 10.89 seconds.
Due to an extended production
run for the 1969 model year due to a lengthy labor strike, sales were
down on the 1970 models to 17,316.[9]1970
small-block power peaked with the optional high compression,
high-revving LT-1
which
produced 370 bhp (276 kW). The 427 big-block was enlarged to 454 cu in
(7.44 L) with a 390 bhp (291 kW) rating. The ZR-1 special package was an
option available on the 1970 through 1972 model years, and included the
LT-1 engine combined with special racing equipment. Only 53 ZR-1's were
built.
[10] The 427 cu in (7.00 L) big-block was enlarged to
454 cu in (7.44 L).
In 1971, to accommodate
regular low-lead fuel with lower anti-knock properties, the engine
compression ratios were lowered which resulted in reduced power ratings.
The power rating for the 350 cu in (5.7 L) L48 base engine decreased
from 300 to 270 horsepower and the optional special high performance LT1
engine decreased from 370 to 330 horsepower. The big-block LS6 454 was
excluded from the de-ratings and it reached its power peak of 425 bhp
(317 kW). For the 1972 model year, GM moved to the SAE Net measurement
which resulted in further reduced, but more realistic power ratings than
the previous SAE Gross standard. Although the 1972 model's 350 cu in
(5.7 L) horsepower was actually the same as that for the 1971 model
year, the lower net horsepower numbers were used instead of gross
horsepower. The L48 base engine was now rated at 200 bhp (150 kW) and
the optional LT1 engine was now rated at 270 bhp (200 kW). 1974 models
had the last true dual exhaust system which was dropped on the 1975
models with the introduction of the federally mandated catalytic
converter and mandatory use of no-lead fuel. As a result, engine power
plummeted with the base ZQ3 engine producing just 165 bhp (123 kW), the
optional L82's output was reduced to 205 bhp (153 kW), and the 454
big-block engine was discontinued. Gradual power increases after 1975
peaked with the 1980 model's optional L82 producing 230 bhp (172 kW).
Styling changed subtly over
the generation until 1978 for the car's 25th anniversary. The Sting Ray
nameplate was not used on the 1968 model but Chevrolet still referred to
the Corvette as a Sting Ray, and 1969 (through 1976) models used the
"Stingray" name as one word, without the space. In 1970 the body design
was updated including fender flares, and interiors were refined
including redesigned seats. Due to the government regulation, the 1973
Corvette's chrome front bumper was changed to a 5-mile-per-hour (8 km/h)
system with a urethane bumper cover. The optional wire-spoked wheel
covers (left) were offered for the last time in 1973.
In 1974 a 5-mile-per-hour (8
km/h) rear bumper system with a two-piece, tapering urethane bumper
cover replaced the Kamm-tail and chrome bumper blades, and matched the
new front design from the previous year. 1975 was the last year for the
convertible, (which did not return for 11 years) and Dave McLellan
succeeded Zora Arkus-D
untov
as the Corvette's Chief Engineer. For the 1976 models the
fiberglass floor was replaced with steel panels to provide protection
from the catalytic converter's high operating temperature and the
Stingray nameplate was dropped after 1976 ending 13 model years where
the names Corvette, Sting Ray, and Stingray were synonymous. 1977 was
last year the tunneled roof treatment with vertical back window was
used, in addition leather seats were available at no additional cost for
the first time. The black exterior color returned after a six-year
absence . The 1978 model introduced the fastback glass rear window
and featured a new interior and dashboard. Corvette's 25th anniversary
was celebrated with the Indy 500 Pace Car limited edition and a Silver
Anniversary model featuring silver over gray lower body paint. All 1979
models featured the previous year's pace car interior and offered the
front and rear spoilers as optional equipment. In 1980, the Corvette
received an integrated aerodynamic redesign that resulted in a
significant reduction in drag. After several years of weight increases,
1980 Corvettes were lighter as engineers trimmed both body and chassis
weight. In mid-1981 production shifted from St. Louis, Missouri to
Bowling Green, Kentucky, and several two-tone paint options were
offered. 1981 models were the last available with a manual transmission
until well into the 1984 production run. In 1982 a fuel-injected engine
returned, and a final C3 tribute Collectors Edition featured an
exclusive, opening rear window hatch.
More Trivia . . .
Pontiac almost beat Chevrolet to the Coke
bottle design body, with their 1965 Banshee, a two seater convertible
sports car that would have been hefty competition for the Corvette. GM
stopped it, and then Pontiac president John DeLorean later became
president of Chevrolet.
T-top does not refer to the shape of the
roof, but rather it is short for Targa Top. The original design was a pure
Targa but body flex demanded the center bar, discovered late in the
design.
Due to policy changes in Chevrolet,
Corvette was treated like all other car lines for the first time, and
quality dropped drastically. With bad publicity in most magazines, policy
was re-thought and Chevrolet quickly restored independence and quality to
Corvette within a few months, but all 1968s carry the stigma of being
"the worse quality" of all Corvettes.
All big block manifolds were redesigned to
actually sink into the lifter valley as the hood clearance was less than
in '67 and back. As such, a 1965 to 1967 big block intake manifold won't
fit in a 1968 or newer Corvette with a stock hood and air cleaner.
The exception to the above was the L-88. It
retained the high rise manifold and also received a special hood, which
was externally different this time.
Emission control equipment was installed on
the first 1968's in the fall of 1967 even though the federal law required
it only as of January 1, 1968.
1968 was the first year AM/FM stereo was
offered as an option.
1968-1972 the coupe's rearwindow was
removeable for more of a true convertible experience
The Sting Ray name was not used on the 1968
Corvette, but returned in 1969… Spelled Stingray.
Corvette had its first all aluminum engine
in 1969 as the ZL-1. It was not the first GM automobile to do so, beaten
by the Corvair in 1960 and the Buick 215 V8.
In 1969, the ignition lock was moved from
the dash to the steering column. It would remain there until 1997 when it
was returned to the dash.
The LS7 engine option, which was never
installed in the 1970 Corvette was $3000.
No Corvettes were painted Black at the
factory from 1970 to 1976.
The only outside difference between the
1971 and a 1972 Corvette is the appearance of the amber front turn signals
and vertical chroming on the egg-crate grills both on the 1972 - that's
it. Minor stuff most people miss.
1972 was the only year for Corvette
"Big Block" engines in the 1968 to 1972 range to have no horse
power sticker on the air cleaner lid.
"Pewter Silver" was only offered
as an exterior color in 1972.
The 1970 - 1972 Corvettes were the last to
feature chrome bumpers front and rear. In 1973, the front bumper changed
to body-colored flexible plastic. In 1974 the rear bumper followed suit.
In 1973, aluminum wheels were again
available as an option, but the same problem that plagued the 1963
aluminum wheels, the inability to hold air, kept these out of the hands of
customers until 1976.
The rear view mirror in the 1974 Corvette
was increased to a width of 10".
The last true dual exhaust was installed in
1974, after that, everything went through a catalytic converter.
1974 rear bumper was 2 pieces, 1975-1982
used a one piece unit.
The awesome 454ci engine was only offered
for 5 years.. 1970, 71, 72, 73, and 1974
Gymkhana Suspension was first introduced in
the 1974 Corvette.
1974 was the last year the Corvette would
be produced to run on "leaded" gasoline.
1975 first year for HEI distributor.
1975 was lowest production year for
convertibles for those years that offered both convertibles and coupes.
1976 Corvette used the same steering wheel
as a Chevrolet Vega for the "Sport Wheel" Option.
1977 last year for the notch back shark.
In 1977 crossed flags returned to the nose
and sides of the Corvette.
1977 saw the redesign of the center console
to accept standard Delco radios, the first year that Corvette didn't have
a Corvette only radio.
The '78 Pace Car was "Black and
Silver" was because it photographed well. Back then, most magazine
articles and ads were still done in Black & White!
The body in 1978 was widened in the rear
fender area. This was discovered by customizers when converting '78 and
newer coupes to convertibles after the convertible production ended in
1975.
1979 Corvette's highest production year.
By Federal mandate, the 1980 Corvette was
the first Corvette to have an 85 MPH speedometer.
1981 the first Corvette to use a computer.
The 1981 Corvette had two cooling fans to
increase engine power.
In 1981, Corvettes were produced with two
different types of paint. Lacquer was applied at the St. Louis plant, and
enamel was applied at the new Bowling Green plant.
In 1982 fuel injection reappeared in the
Corvette after a 17-year hiatus.
