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1963
Chevy Impala
Some history & technical specifications
1963
CHEVROLET Impala
Super Sport 409
V-8 with Powerglide
(Published in "Car
Life", March 1963.)
ONE
OF THE automotive world's most interesting developments for
1963 is the wider application of huge, relatively slow-turning
V-8 engines. Both Chevrolet (at 409 cu. in.) and Pontiac (421)
have followed the trend set by Chrysler (413) a few years ago.
Ford/Mercury (with 390), Dodge/Plymouth (383) and Oldsmobile
(394) already had hydraulic lifter, single 4-barrel carburetored
versions of earlier racing engines.
Chevrolet's high-torque model is a variation of its own successful
409-cu. in. racing engine (one won Stock Eliminator category
in the NHRA championship drag races last summer) and follows
the now-established pattern: hydraulic lifters, 4-barrel carburetor
and a camshaft of more modest duration and overlap. Instead
of developing the 425 bhp @ 6000 rpm of the racing engine, it
produces 340 bhp @ 4600 rpm - a much more docile and livable
amount. More important, the torque of this very large engine
is no less than 420 lb.-ft. @ 3200 rpm, where the all-out engine
produces only 425 lb.-ft. and that at 4200 rpm!
This
means that the engine in our test car develops more torque than
the 425-bhp model over the speed range most used, i.e. from
500 to about 3500 rpm. Stated another way, the high torque 409/340
engine's advantage extends from 10 to 80 mph and at any speed
in between it will have more high-gear punch than the 409/425
engine.
Do not, by the way, confuse this 340-bhp engine with the similarly
rated engine option in the Corvette. All Corvette engines are
the same size (327 cu. in.) and because of the (relatively)
small displacement the 327/340 Corvette engine shows only 344
lb.-ft. @ 4000 rpm, 18% below the 409/340 engine.
With so much
torque available it is quite surprising to find that the standard
axle ratio is 3.36:1 (even the standard 230-cu. in. 6-cyl.
models get a 3.08 axle ratio). However, the 409-powered models
come with larger 8.00-14 tires as standard. At 60 mph this
big 409 is still turning over at a modest 2600 rpm.
Coupled to this powerhouse in Car Life's test '63 Impala SS
is Chevrolet's traditional 2-speed Powerglide automatic transmission,
the first of this combination offered to the general public.
While the Powerglide has only one geared ratio (1st), the
torque converter gives the benefit of an extra-low low and
in effect there are 3 speeds forward, with an overall starting
ratio of 12.4:1This, in our test car, was low enough to produce.
any amount of wheelspin desired, even on dry pavement.
As a matter of fact, there is so much torque that punching
the throttle wide open at 40 mph will produce a very inspiring
screech from the driving wheels and the car will literally
leap ahead like the Impala for which it was named. However,
it is easy to manage and wheelspin, too, is always controllable.
Keep in mind one important proviso, however: it is not good
judgment to put your foot down too hard when coming out of
a corner, or when crossing a wet spot on the street. With
so much acceleration available it is possible to pull out
of a side street in front of oncoming traffic and punch it
so hard the car will spin out!
Our
usual data panel tells the acceleration story-a 0-60 time
under 8 sec. isn't unusual these days but the real indication
of performance is the 0-100 mph time. Last year (CL, Sept.
'62) we tested one of the really hot Chevrolet 409 combinations,
and with a 4-speed transmission. It romped to 100 corrected
mph in 9.4 sec.! The Powerglide 409 isn't quite that much
of a dragster but it is only 2 sec. slower to 60 mph and it
gets to an indicated 100 mph on a very honest speedometer
in just under 20 sec. As a further example of what might be
called practical performance vs. the 409 Super Stocker, the
elapsed time for the 1/4 -mile is only 3 sec. longer, with
(again) Powerglide. The speed at the end of the 1/4-mile was
exactly 90 mph, by the way.
So
when the performance is there, what are the disadvantages? There
are a few of course, but nothing like those found in a typical
car set up for drag racing and little else. This is a practical,
docile, fun-to-drive car that is equally at home on the street
or the expressway. The engine isn't quite as smooth and quiet
as the 283 or 327 powerplants, but the difference is barely
noticeable. Fuel consumption is a little heavier; we got an
overall average of 12 mpg for 700 miles of assorted driving,
which included taking occasional advantage of the tremendous
performance. Here is a case where, even more than usual, the
driver is the key to economy. The extra urge is hard to resist
and a lead foot would have to be satisfied with 10 mpg. On the
other hand, a Mobilgas Economy Run type of driver could probably
squeeze 16 mpg out of the car under ideal highway conditions.
Here
we might go back to our earlier remarks regarding the surprising
choice of axle ratio (3.36:1). This ratio was obviously chosen
to give very high performance, rather than economy. In our earlier
test of the new 6-cyl. engine (Car Life, November 1962) we remarked
that "acceleration in the 40-60 mph range is decidedly weak."
This would be expected from its performance factor of only 81.6
cu. ft. of explosion volume per ton-mile. The 409 V-8 factor
is 150 cu. ft./ton mile, slightly higher than our December test
car, a Sting Ray with 3.36 axle. Most buyers of the 409 would
be well advised to specify the 3.08 axle, ratio. This is a change
of only 8.3% and won't affect the performance by much, yet will
improve gas mileage and, incidentally, raise the top speed to
nearly 130 mph (the valve lifters pump up at just over 5600
rpm). As a matter of fact, it is unfortunate that Chevrolet's
fastest axle ratio is 3.08. Pontiac, for example, offers ratios
of 2.56, 2.69 and 2.87. Even the 390-cu. in. Cadillac has a
standard axle ratio of only 2.94, giving a performance factor
of 99.5 cu. ft./ton mile, which translates into very acceptable
acceleration and hill-climbing ability.
POWER CURVES for the new 409/340 show a torque range of 4000
rpm at 360 lb.-ft. or more but a sharp gross horsepower peak.
Other
than the above, our principal objection to this package stems
from the slow steering (power) on a car which literally demands
very quick steering in case the rear end starts to slide out
from too much throttle pressure. The ride too, in typical GM
fashion, is quite soft and anyone contemplating much cross-country
driving should order the heavy-duty springs and shocks. It would
also be a good idea to order the metallic brake linings.Other
than the above, our principal objection to this package stems
from the slow steering (power) on a car which literally demands
very quick steering in case the rear end starts to slide out
from too much throttle pressure. The ride too, in typical GM
fashion, is quite soft and anyone contemplating much cross-country
driving should order the heavy-duty springs and shocks. It would
also be a good idea to order the metallic brake linings.
IMPROVED POWERGLIDE was adopted in 1961, allowed Chevrolet
engineers to harness 409 to automatic transmission. Complete
unit was strengthened, then encased in aluminum.
Because
the 409 engine is about 100 lb. heavier than the 283-327 V-8s
and most of this extra Weight is on the front wheels, there
is more understeer than usual-a good feature to help offset
the oversteering capability of so much power at the rear wheels.
This weight bias also contributes to better straight-line stability
but makes the car skitterish in vigorous cornering.
The brakes are something else, though to our surprise they survived
our standard brake test of two crash stops in succession from
80 mph. However, the tremendous weight and speed potential of
this machine is a force to be reckoned with and a hard driver,
or one living in a mountainous area, should order the heavy-duty
metallic brake option we mentioned earlier.
The
Impala SS, of course, carries the most luxurious, bucket-seat
interiors Chevrolet can put into its cars. It has a center
console which houses a small odd-parcel locker and serves
to bring the Powerglide shift lever into the driver's reach.
Although nicely assembled with a chrome shift guide around
it, the lever has no provision for lighting and a nighttime
driver must either grope for the correct slot or turn on the
bright interior lights. We must praise the electric tachometer
mounting as the first sensible one we've seen on a production
'63 model. It is directly in front of the steering wheel,
in the speedometer "tunnel" and is so located that the driver
can be aware of engine rpm withoutactually having to remove
his eyes from the road. The other instruments are much less
easy to read, being located at the bottom end of the aforementioned
tunnel.
The driving position is awkward: the seats, while comfortable
and luxurious, are too low and the steering wheel projects
too far back. (A solution to that continuing problem is to
replace it with a flat, racing type wheel which would move
the plane of the rim at least 5 in. closer to, the dash.)
Luggage space is tremendous, as would be expected.
TWIN 4-BARREL version of the 409 has mechanical lifters, hotter
valve timing and now produces a rousing 425 bhp at 6000 rpm.
TRUNK WELL in Chevrolet's tail adds to its already huge capacity.
Although difficult to reach, spare is nicely out of the way.
But,
while we criticize some of the minor things about the car, we
can enthuse over its general concept. Big and strong, with a
smooth transmission and plenty of muscular draft horses up front,
it begins to approach the ultimate in U.S. performance cars.
References:
www.55-57chevys.com
"Car Life", March 1963
LINKS:
View list of all other Chevrolet diecast
Toy
Wonders link to 1/24 scale vehicles
Toy Wonders link to 1/18 scale vehicles
Toy
Wonders diecast directory
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