FAQ about GM LS and LS-inspired
Q) Why do I want an LS or a Vortec
A) Superior aluminum cylinder heads on
all LS engines and most Vortecs as well. Stock, they flow as much or
more than many of the fully ported “double-hump” heads. How about
6 bolt mains? 300Hp, 400hp, 500hp versions available...stock! And we
are not even talking about the forced induction versions like the LS9
Plus, they are not 15 to 57 years old
like most small block Chevy motors (crate motors excluded)!
No distributor to hit the firewall when
you are swapping engines like the Gen I small blocks.
Roller lifters, stock. Roller fulcrums
on the rocker arms, stock. (not a roller tip on the rocker arm). 2.00
intake valves on the “small heads”, 2.165” intake valves on the
Rectangular port heads, and 2.200” intake valves on the LS7 heads.
Kinda makes the old 2.02” intake valves on the old “double-hump”
heads look inadequate.
Lots of aftermarket support so you have
lots of choices when it comes to parts to make more power.
Now do you realize why so many
enthusiasts are swapping LS and Vortecs into their race cars and
Q) Do I have to get a LS1? They only
made so many of the Camaros, Vettes, GTOs and the LS1 LS6 LS2 maybe
hard to find.
A) Do you realize how many Chevrolet
and GMC trucks and SUVs have been built with V8 engines since 1999?
Vortecs are plentiful, and a whole lot cheaper than LS engines at the
Q) Are LS and Vortecs the same?
A) Sorta. All LS series engines to date
have aluminum blocks with aluminum heads. The Vortec 4.8 5.3 6.0 6.2
all use aluminum heads (except some early 99-01 6.0L) and most
Vortecs have the same block design as a LS, but made in cast iron.
There are even some aluminum block versions of the Vortec used.
Basically, the LS-inspired Vortecs have
the same architecture as the LS Family of engines. Be aware that
there were some GM truck engines that have the “Vortec” name, but
are of a different engine family. Vortec 7.4 and 8.1 are the same
design as the old Big Block Chevy. Vortec 5.7 are more similar to the
Gen I small block Chevy.
For the purposes of this website,
references to “LS-inspired Vortecs” and “Vortec engines” will
refer to the Gen III/Gen IV 4.8, 5.3, 6.0, 6.2 engines only.
Q) Do I have to run fuel injection if I
swap an LS or LS-inspired Vortec into an older vehicle?
A) No, you do not have to run
injection. There are intake manifolds available for the cathedral
port versions of the LS & Vortec to run a carb. MSD also makes a
coil driver box to run the 8 separate coils when you are running a
carb and not running the ECU.
Q) Were the LS engines introduced in
numerical order? IE LS1 LS2, etc.
A) No, the LS1 was introduced first.
Then came the LS6,which was an upgraded LS1. LS2 came next. LS7 in
the Z06 Corvette. LS3 used in the manual trans version of the 5th
gen Camaro SS (2010+), 2008+ Corvettes, the few Pontiac G8 Gts that
were sold. Automatic versions of the Camaro SS were equipped with the
L99. LS9, supercharged used only in the Corvette ZR1, LSA,
supercharged used in the 2nd gen Cadillac CTS-V and a
version of the LSA to be used in the upcoming Camaro ZL1. There is a
LS4 which is a FWD version used in Monte Carlo SS & Impalas, but
it is not a good RWD swap candidate and the performance aftermarket
has not been highly supportive of this particular engine.
Q) Do parts interchange between all
A) Yes and No.
Cathedral port heads must be used with
a matching intake manifold with the cathedral ports. Same hold s true
for the rectangular port heads as well as the raised port rectangular
port heads on the LS7. Rectangular port heads (LS3 L92 L99) should
only be used on engines with 4.00” bores and larger, basically the
6.0 and 6.2 L engines. The LS7, raised rectangular ports should only
be used on engines with bores larger than 4.100 inches. Valve to
cylinder wall clearance issues and valve shrouding are the reasons
why this is recommended.
Cathedral port heads use rocker arms
with no offset and 1.7 ratio. Rectangular port heads require an
offset rocker arm on the intake side only. These are also 1.7 ratio.
LS7 raised rectangular port heads require offset rocker arms on the
intake side similar to the Rectangular Port heads but use 1.8 ratio
on both the intake and exhaust.
Most LS and Vortec engines use a 3.622”
stroke crankshaft, but the LS7 uses a 4.00” stroke with and
extended snout to drive the dry-sump oil pump. 4.8 Vortecs use a
3.27” stroke crankshaft. All Gen III engines (LS1, LS6, Early 05
LS2, Vortec 4.8 5.3 6.0 prior to 07 & w/o AFM) use a crankshaft
with a 24 tooth reluctor wheel. All Gen IV engines (except the Early
05 LS2) use a 58 tooth reluctor. The crank sensor and ECU or ignition
controller must be “matched up” with the correct reluctor wheel
for the engine to run. So if you are buying a used engine and plan on
running the factory fuel injection/ignition system, get the matching
ECU. (Don't forget to get the matching accelerator pedal assembly and
associated wiring if it is a DBW (Drive By Wire) throttle body. All
LS & Vortec crankshafts are 6 bolt prior to 2009. In 2009, the
LSA crankshafts use a 8 bolt flange and the LS9 crankshafts use a 9
Factory connecting rods, made from
powdered metal (6.098”), are similar for the 5.3 5.7 6.0 6.2
engines. 4.8 use a longer rod (6.275”) while the LS7 uses a
shorter, titanium rod (6.067”). The LS7 and LS9 rods use a
different rod bearing than the other engines.
Gen III engines have a camshaft
position sensor located on the back of the block and the camshaft has
a “wheel or locator lug” near the rear camshaft journal. Early 05
LS2 have a camshaft sensor located on the front cover and “reads”
the lugs on the cam sprocket. Both Gen III and this early 05 LS2 are
referred to as “2x”. The Gen IV engines late 05 and later use the
same front cover location but have a different cam sprocket and is
known as “4x”. Be aware that there are both 3-bolt and 1-bolt
versions of the cam sprockets for the “4X” cam position sensors.
You have to make it all work together.
Q) Can I use a Vortec truck engine to
swap into a car?
A) Yes, but you may have to do some
“mixing and matching” of LS and Vortec components to make it
work. Vortec truck intake manifolds are rather tall and may not fit
under the hood of the vehicle you are swapping this engine into.
Solution, use a LS style intake which has a much lower profile.
Remember that the manifold port shape must match to the cylinder
heads being used. Cathedral to Cathedral, Rectangular to Rectangular,
LS7 to LS7. You will also have to swap fuel rails, throttle body etc.
The water pump may have to be changed
as the truck style pumps have an outlet/inlet the sticks up in front
of the throttle body when you switch to the low-profile, LS style
intake manifold. Also as part of this, you may have to switch the
other belt driven accessories to a car style due to clearance issues
with the frame (A/C compressor may hit the frame rail and need to be
relocated) and or the hood (high alternator position used on trucks).
Q) Why would I want a cast iron truck
block when I can have an aluminum block?
A) Many reasons. The weight “penalty”
is only about 65-80 pounds. But a Vortec cast iron block is still
about 30 pounds lighter than the old, Gen I small block Chevy! Vortec
Cast Iron truck blocks are much more plentiful than the aluminum
blocks and thus they should be cheaper. How many Chevy, Hummer &
GMC trucks and SUV's have been built with V8 engines since 1999?
Millions! How many LS engines in Camaros, Corvettes, GTOs , G8 GT and
a few other applications, not quite as many!
Another advantage the cast iron Vortec
blocks have over the LS aluminum blocks is the ability to over bore
the cylinders. Aluminum blocks have rather thin cast iron cylinder
liners that severely limit the possible overbore sizes. Cast Iron
blocks can be bored much larger than their aluminum counterparts
without the same concerns. It is possible to bore a 5.3 cast iron
truck block to 5.7 so you can use the LS1 and LS6 pistons. Do you
want me to tell you about boring and stroking a 5.3 cast iron truck
block to make a 383? Stroker kits are available!
If you need more information and parts
for your LS or LS-inspired Vortec engine, head on over to the LS
Speed Shop where all we do is LS and Vortec parts and accessories.
Parts for you LS or Vortec engine swap or parts for your New Camaro,
GTO, CTS-V, Corvette, and soon Chevy & GMC trucks.