The 1957 Corvette included a larger
V-8 and, as a mid-year addition
to the options list, a four-speed
manual gearbox that had long been
demanded by enthusiasts. The Corvette’s
appearance didn’t change — not
that it needed to — except that
the bodyside “coves” could
now be finished in a contrasting
color as a $19.40 option.
The
1957 Corvette added fuel
injection
for improved
engine performance.
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The 283-cid V-8 has become one of
Chevy’s most revered engines —
the definitive small-block enshrined
by a generation of car enthusiasts
and all the collectors who followed.
It was essentially the existing
265 engine that had been bored out
1/8-inch (to 3.875 in.; stroke remained
a short 3.00 in.). In Chevrolet
passenger cars, the 283 delivered
185 bhp in base form, but the standard
Corvette version with a four-barrel
carburetor developed 220 bhp at
4800 rpm. Dual four-barrels took
it to 245 and 270 bhp, and GM’s
newly developed “Ramjet”
fuel injection system yielded 250
or 283 bhp. The last was the magic “one-horsepower-per-cubic-inch”
threshold, and Chevy ads blared
the news. (It wasn’t a first, though;
Chrysler had actually exceeded that
goal the previous year with its
355-bhp 354-cid hemi V-8 in the
300B.)
Fuel injection was a foreign concept
— literally — to Detroit automakers
in the 1950s. Chevrolet turned to
the technology as a way of gleaning
added performance out of its two-year-old
V-8 while its competitors were preparing
all-new eight-cylinder powerplants
of their own. The engineers borrowed
a page from the European automakers’
performance books and settled on
obtaining more horsepower via a
more precise fuel metering system
than a carburetor allowed, namely
fuel injection. Model year 1957
was closing fast, so a development
team was formed — and hustled.
In a relatively short period of
time, the engineers put together
a fuel injection system that appeared
to be relatively inexpensive to
manufacture and promised significant
power gains. Yet initial dyno-testing
showed the “fuelie” to
be no more powerful than a standard
dual-carburetor V-8. So it was back
to the lab for more research.
Ultimately Chevrolet and GM’s Rochester
carburetor division came up with
a workable system that not only
increased top-end output but spread
power over a wider rpm range. Reliability
problems surfaced quickly, which
together with the option’s high
price tag — $500 — rendered fuel
injection a scarce commodity. Installations
ran to only 240 in a total ’57 production
run of 6,339 Corvettes. Ramjet fuel
injection was subsequently dropped
from Chevy’s other passenger car
lines after 1958, though it remained
as a Corvette option through 1965.
Despite its problems, fuel injection
provided the necessary performance
ability. “Fantastico!”
began one ad that pictured a Corvette
being unloaded from a freighter,
a half-covered Ferrari just visible
in the background. “Even in
Turin, no one has fuel injection!”
Ironically in view of the hubbub
about “1 h.p. per cu. in.,”
the top fuelie actually delivered
closer to 290 bhp — more than the
advertised 283. This was attained
on 10.5:1 compression, shared with
the dual-carb 270-bhp engine. The
milder 250-bhp fuelie ran a lighter
9.5:1 squeeze, same as that of the
245-bhp twin-carb unit. Some historians
think that in its zeal to promote
Ramjet, Chevrolet deliberately underrated
power on the dual-carb engines.
The 283-cid/283-bhp motor was sold
as a $484.20 option; it carried
the EL order code and should not
be confused with the EN racing version,
which, at $726.30, was sold as a
package complete with column-mounted
tachometer and a cold-air induction
system. Chevy warned potential buyers
that the EN option was not for the
street and actually refused to include
heaters on cars equipped with the
racing package.
The
1957 Corvette featured a
V-8 enlarged to 283 cubic
inches
and offered in
five versions.
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In the long run, the four-speed
manual gearbox option was probably
more significant than fuel injection
for the Corvette’s overall performance
aura. Priced at only $188.30, Regular
Production Option (RPO) 685 was
essentially the existing three-speed
Borg-Warner transmission with the
reverse gear moved into the tailshaft
housing to make room for a fourth
forward speed. Ratios were again
closely spaced: 2.20:1 (1st), 1.66
(2nd), 1.31 (3rd), and 1.00 (4th). “Positraction,”
Chevy’s new limited-slip differential,
was a separate option available
with four different final-drive
ratios to help get the most out
of the new engines and gearbox in
each particular driving or competition
situation.
For the 1957 Corvette — answering
the previous generations’ complaints
about handling and braking deficiencies
— Chevrolet also issued RPO 684.
This was a $780.10 “heavy-duty
racing suspension” package
comprising heavy-duty springs, a
thicker front anti-sway bar, Positraction,
larger-piston shock absorbers with
firmer valveing, a faster steering
ratio that reduced turns lock-to-lock
from 3.7 to 2.9, and ceramic-metallic
brake linings with finned ventilated
drums. Add the 283-bhp fuelie V-8,
and you had a car that was ready
to go racing right off the showroom
floor.
In almost any form, the ’57 Corvette
delivered certifiably staggering
performance. Motor Trend
clocked a 250-bhp fuelie at just
7.2 seconds in the 0-60-mph sprint.
The 283-bhp version was even more
formidable, with Road & Track
running the same test in a four-speed
with the short 4.11:1 final drive
in just 5.7 seconds; it breezed
through the quarter-mile in 14.3
seconds at better than 90 mph and
sailed on to a maximum of 132 mph.
Motor Trend took a version
with the 283-bhp engine, dual exhausts,
special cam, and solid lifters all
the way up to 134 mph.
Learn about other Corvettes
in this generation: