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LS and LS inspired Vortec FAQ (Frequently Asked Questions)

FAQ about GM LS and LS-inspired Vortec engines.

Q) Why do I want an LS or a Vortec engine?

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 & LSA.

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 street machines?

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 salvage yards.

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 these engines?

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 bolt flange.

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.