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How To Install A Modern LS3 V-8 Into a 1962-1967
Chevrolet Nova
Text and photography by John Kiewicz
The day had finely come. Years of a drivetrain that consisted of a 600 horsepower old-school V-8 backed
by 4.88:1 gears had taken its toll. The car was temperamental, it guzzled gas like the fuel tank had a hole
in it, and it always required maintenance to keep in top tune. Frankly, the car was no longer fun to drive. I
now wanted to simplify, but I didn't want to settle for an engine that was anemic.
Today's modern engines are amazing. Combined are strong power (often over 400 hp), good fuel economy, a smooth idle and excellent reliability. Although controlled by a computer and a labyrinth of wires,
installation is relatively easy thanks to swap parts available from aftermarket vendors.
Through conversation I learned of a guy who was in the midst of pulling the stock LS3 V-8 from a 2011
Camaro SS so the car could be fitted with a twin-turbocharged LSX V-8 that would crank out over 1,000
horsepower. For $5,000 the owner agreed to sell the stock LS3 (that made a stout 426 hp) along with all
the factory accessories, exhaust manifolds and catalytic converters.
While many LS-series V-8 swaps have been done, I had yet to personally see an LS3 in a 1962-1967
Chevrolet Nova. With a tight engine bay, bulky shock towers, and rear-style (versus traditional front-style)
steering linkage, an early Nova presents numerous challenges. However, with the help from Street &
Performance, over the course of a few months I had the modern LS3 V-8 shoehorned into the 1966 Nova.
Besides selling custom swap parts, most all of the factory GM parts (GTO oilpan, Corvette fuel rail covers,
oxygen sensors, etc.) mentioned in this story can be obtained directly from Street & Performance as well.
Follow along to see what it takes to do the swap.
The LS3 V-8 is flanked by swap parts from Street &
Performance that include a custom wiring harness and
computer, special motor mounts, an oilpan to clear the
Nova's unique steering linkage, fuel system connections,
exhaust headers, a throttle-by-wire gas pedal, and much
more. A Rock Valley fuel tank incorporates the required
high-pressure fuel pump and a Quick Time bellhousing
allows the modern LS3 to mate with the old-school Muncie
4-speed.
The "old" engine produced over 600 horsepower
thanks to a big roller camshaft, aluminum heads,
and 8 psi boost from a centrifugal supercharger.
Fun? Yes. Temperamental? Yes. Time to go? Yes.
With the old engine
removed, we took the
opportunity to
clean and paint engine
bay before installing
the new LS3. Here, the
engine bay has been
sanded and primered.
Afterwards, the engine
bay was painted with a
semi-flat black paint
The A/C compressor fitted to the LS3 contacted
numerous points in the
engine bay, thus it was
removed for clearance.
No worries, however, as
this Nova was not originally equipped with air
conditioning.
After the
engine bay
was painted, a
test fit of the
LS3 V-8 was
done to identify
any interference issues.
Although it did not
cause interference
with the engine compartment, the LS3's
bulky power steering
pump was removed
for added space as
this 1966 Nova was a
manual steering car.
Due to the A/C and P/S pumps being removed, new
serpentine belt routing was required. After some
head scratching, it was determined that by removing
an unneeded idler pulley, a serpentine belt could be
routed as shown which would retain the original
rotation direction of the remaining accessories. Due
to the removal of several accessories, a shorter belt
(Goodyear Gatorbelt, PN 4060578) was used.
During the initial test fit of the LS3 engine, it was
immediately obvious that the Camaro's stock oilpan
would not work with the Nova's unique rear-style
steering linkage. In this case, a 2006 Pontiac GTO
oilpan (GM, PN 12599397) was used to generate
proper clearance. The stock oilpan for the Camaro
was drained of oil to prevent a mess during
removal. Afterwards, the numerous M8x1.25 metric
thread retaining bolts were removed and the oilpan
was dropped down.
Remove the stock windage tray and replace it with a 2004-2006 Pontiac GTO windage tray
(GM, PN 12558189). The GTO oilpan uses a different oil pickup tube (GM, PN 12572654)
than used with the Camaro oilpan. Removing the old pickup is easy, then the new pickup
can be bolted into place. Installing the GTO oilpan is simple. Locate the oil pickup in the
small opening within the oilpan, align the bolt holes and then thread in the original bolts.
With the Pontiac GTO oilpan fitted to the Camaro LS3 engine, ample clearance is afforded
for the Nova's rear-style steering linkage assembly. Using a GTO oilpan requires using the
proper GTO dipstick assembly (PN 92066941). During installation, the dipstick tube was
bent slightly to allow the assembly to securely affix via an unused bolt hole located on the
front of the passenger side cylinder head.
The driver-side of the LS3
block had miscellaneous
coolant hose adapter that
came into contact with
the custom motor mounts
from Street & Performance. Thus, the adapter was
removed the hole was sealed using a factory plug (GM,
PN 11609289) sourced from a local Chevrolet dealership or S&P.
Street & Performance custom motor mounts allow original V-8 motor mounts to connect to a new LS3
engine. Each motor mount is labeled which eases installation. The Street & Performance motor mount
adapters bolt to the side of the LS3 using a variety of special bolts. Be sure to add some thread locking
compound to the 10 mm bolts during installation. With the aluminum adapters in place, bolt on the original
motor mounts using the supplied hardware.
With the LS3 we wanted to retain the manual transmission
that was already in the vehicle. Thus, a Quick Time bellhousing (PN 895837) was used to connect the new LS3 to the
original Muncie 4-speed. The bellhousing uses a motor plate
that involves removing the stock clutch and flywheel so that
the plate can be properly positioned. After the Quick Time
bellhousing motor plate was installed, the stock flywheel was
reinstalled using new M10x1.5 bolts (ARP, PN 134-2201).
After the stock flywheel was installed, the stock LS3 clutch
was reinstalled using new M11x1.5 bolts (ARP, PN 330-2802).
Before installing the Quick Time bellhousing, a new clutch fork
(Classic Industries, PN C926321) and heavy-duty throw-out
bearing (Hays, PN 70-101) were fitted. With the clutch in
place, the Quick Time bellhousing is an easy install. Not only
does the bellhousing mate the old 4-speed to the new LS3
engine, but it also has full SFI certification for added safety.
After installing the new oilpan, S&P
motor mounts and hybrid bellhousing,
the LS3 was lowered into the engine
bay.
The magic of the Street & Performance wiring harness is that every connection has its own easy-toread label- thus, properly installing each of the wires
is simple. Begin the wiring harness install by draping
the Street & Performance wiring harness over the
engine in its approximate position. Then, attach each
of the connectors as each wire label indicates. While
it may seem daunting, we had the engine wiring harness installed in less than 20 minutes.
Here the
alternator
wire easily
clips into
place. The
connection
for the
mass airflow sensor
can also be
seen.
LS-series engines feature individual
coil packs for each cylinder.
Connecting the wiring is simple thanks
to the custom wiring harness from
S&P. Installing the connectors for the
eight fuel injectors was easy thanks to
clear markings on each wire. In addition, all of the S&P wiring was an exact
fit- meaning that there wasn't a bunch
of extra wire length left over after making the various connections.
On the passenger side of the
LS3 block (just forward of the
starter) is the crankshaft sensor and one of the two knock
sensors. Thanks to the labels
on the Street & Performance
wiring harness, properly connecting the wires is easy.
When ordering the custom wiring harness from Street
& Performance, you indicate where you would like to
mount the computer. By relocating the horns, an area
on the driver side front fenderwell afforded space for
the computer installation.Once the computer was
mounted to the fenderwell, the two main wiring connectors were clipped into place. The connectors and
the computer are color coded, so installation is
straightforward.
Here is the final look at the installed computer,
various relays, and fuse block that are all part of
the Street & Performance wiring harness. Notice
how the horns have been reused, but relocated
slightly.The modern LS3 engine relies heavily on
myriad electrical connections. Thus, a good
grounding system is a must. In addition to the
ground straps built into the wiring harness, three
separate heavy-duty 4-gauge ground straps were
mounted at the front, side and rear of the LS3
engine.
When bringing home
the LS3, two of the
spark plug wires
were damaged.
Buying new wires
from Chevrolet was
surprisingly expensive, so we upgraded to 8.5 mm.
At the rear of the LS3
intake manifold is a large
port that provides vacuum
to the power brake assembly in the Camaro SS.
Being that this 1966 Nova
uses manual brakes, the
vacuum tube was removed
and the port was plugged.
If you choose to run an external oil pressure gauge inside the car,
you'll need to install an adapter such as from Street & Performance.
Remove the stock oil pressure sensor from the rear of the engine,
thread in the new S&P adapter and then thread the original pressure
sensor into the top of the adapter. The small brass connector is
where the external oil pressure gauge line will connect.
While the stock thermostat housing could be
used, it made for trickier
routing of the lower radiator hose. Thus, a 360degree adjustable thermostat housing from
S&P was used to generate a cleaner installation.
To provide a more clean
installation, heater hoses
with 90-degree moulded
ends were used. A 3/4inch heater inlet hose
(Goodyear, PN 63936)
and a 5/8-inch heater outlet hose (Goodyear, PN
63836) were trimmed
down in length and then
installed.
Because the LS3 does not have provisions to
run a manual fan, the engine swap requires the
use of an electric fan assembly. The previous
supercharged V-8 used a Griffin heavy-duty
aluminum radiator with a built-in electric fanso the setup was reused for the LS3 install. To
operate the electric fan assembly fitted to the
Griffin radiator, a temperature adjustable switch
assembly was used from S&P. Simply remove
the original petcock, thread in the supplied fitting, connect the copper temperature sensor,
and then wire the switch assembly.
Using a few pieces of wire
coat hanger, the approximate shape/length of the
upper and lower radiator
hoses was determined.
Afterwards, some time
was spent at a local auto
parts store looking though
hundreds of hoses to find
the right bends. For the
upper hose, a hose
(Goodyear, PN 61494)
was used with 5 inches
cut off the radiator side
and 1 inch cut off the
engine side. The lower
hose (Goodyear, PN
60687) required cutting 1
inch off the radiator side
and 3.5 inches cut from
the engine side.
The original intent was to
use the stock LS3 airbox,
but its large size wasn't
working in the Nova's small
engine bay. Thus, the
mass airflow sensor mount
was cut off the plastic airbox to be fitted to a custom
air inlet system.
After cutting the
mount from the
factory airbox, the
new mass airflow
sensor was bolted to the original
plastic mount.
A custom air inlet system
was fabricated using 4inch diameter silicone
hose and mandrel bent
aluminum tubing. After
measurement, Six 5-inch
sections of the tube were
cut off leaving the proper
length of mandrel bend.
Available from S&P, a
conical air filter and tubing.
At the front of the driver side
cylinder head is a tube assembly that allows steam accumulated within the cooling system
to be removed. The line
should be connected to the
highest point of the cooling
system, so a fitting was heliarc
welded to a location at the top
of the radiator and then a hose
was added to connect the two.
The end of the 4inch diameter silicone hose elbow
(also available in
polished or chrome
aluminum from S&P)
was trimmed slightly to clear the radiator assembly.
The PCV valve (located at the rear of the driver
side valve cover) needed to be connected. The
PCV should connect rearward of the mass airflow
sensor but forward of the throttle body. A brass connector installed in the inlet system is used to connect the PCV.
The original intent was to use the stock castiron exhaust manifolds. However, the bulky
size of the manifolds caused an interference
with the Nova's large shock towers. Thus, a
set of thermo coated custom headers from
S&P were used. As can be expected,
installing headers is a tight fit. To solve this
problem, S&P designed a set of custom fit
headers for an LS3 in an early Nova.
The modern LS3 engine requires
the use of oxygen sensors to continually monitor the exhaust emissions so that the computer can
adjust calibrations accordingly.
Within the S&P exhaust headers
are integrated bungs used to mount
the oxygen sensors-one O2 sensor
mounted in each exhaust header.
With the LS3 we wanted to retain the
manual transmission that was
already in the vehicle. Moreover, we
wanted to reuse the factory bellcrank
that actuates the clutch assembly.
However, due to the width of the LS3
the stock bellcrank was too long.
Thus, about ¾-inch of the bellcrank
was removed and then the assembly
was welded back together.
Because the LS3 cylinder
block had no provisions for
a cylinder block mounted
pivot ball to actuate the
clutch bellcrank, a piece of
¼-inch thick steel was used
to fabricate a bracket that
allowed for a factory pivot
ball (Classic Industries, PN
KW201) to be fitted.
Mounted under the battery tray is a
Corvette-style fuel filter that also serves
double-duty as a fuel pressure regulator. Because we were using a new fuel
tank, new fuel lines and such, an extra
fuel filter was installed in-line just for
the initial fire-up of the engine. Later,
the extra filter will be removed and the
Corvette filter will remain.
After determining
where the fuel
filter/regulator would
mount, a measurement
was made and a custom length of highpressure fuel line (with
AN fittings on each
end) was installed.
Here you can see
how the fuel line is
routed away from
any hot sources
and is kept in position using Adel
clamps mounted at
different points on
the engine.
Due to the LS3 using a high-pressure fuel pump,
a new larger diameter fuel inlet line was installed.
The LS3 engine requires a return fuel line to route
unused fuel back to the gas tank, so another fuel
line was installed to serve as a return line. Here
the lines are being mocked up, but afterwards
Adel clamps were used to securely hold the lines
while rubber grommets were fitted in the areas
where the fuel line went through the fenderwell.
The stock fuel
tank was
removed and
then the
underside of
the trunk floorpan was
cleaned and
painted.
To provide proper tankto-floorpan clearance,
AN fittings with 90degree elbows were
threaded into the in-tank
fuel pump mounted
within the Rock Valley
stainless-steel fuel tank.
Later on, if the fuel lines
need to be disconnected, the AN lines will
make the task simple.
The Rock
Valley fuel
tank was lifted into position using a
floor jack,
then the new
stainless-steel
tank retaining
straps were
bolted into
position.
The LS3 engine requires the use of a throttle-by-wire
gas pedal. Street & Performance sells many varieties,
but we went with a 2008 Corvette version (GM, PN
25835421) as it more closely resembled the stock
pedal. Remove the stock pedal assembly, fit the new
pedal as space permits, and then drill the required
mounting holes in the firewall. Because our pedal was
mounted in a slanted area of the firewall, some bolt
spacers were cut with angled ends to provide proper
alignment.
Once you've drilled the
proper holes in the firewall, the new throttle
pedal attaches using
two bolts. Once
installed, verify that the
throttle pedal has full
range of motion. If not,
some shims may be
required to provide
proper pedal clearance.
Once the
throttle-by-wire
gas pedal is
installed,
attach the
proper connector that is
clearly labeled
on the Street &
Performance
wiring harness.
The stock engine cover used with the
Camaro was too large and bulky for
our tastes. Thus, a set of Corvette
LS3 fuel rail covers (GM, PN
12600987, driver side; PN 12600988,
passenger side) were installed to
improve underhood looks.
Here is the final look of the LS3 in the 1966 Nova.
While the Camaro SS LS3 was factory rated at 426 horsepower, the LS3 in the 1966 Nova SS is
likely making over 450 hp thanks to Street & Performance's custom tune on the computer, free flowing exhaust headers, a more free breathing air intake system, 8.5mm spark plug wires, and the elimination of the A/C and P/S assemblies. With 450+ hp on tap, the 3,020 pound Nova should be plenty
fun to drive.
Sources:
Street & Performance; 479.394.5711; www.hotrodlane.cc
Rock Valley Antique Auto Parts; 800.344.1934; www.rockvalleyantiqueautoparts.com