The LS2 is a 6.0L, Gen. 4, aluminum small block engine that came in both cars and trucks.
The engine specs and information we’re sharing here are for the LS2 that was used in GM trucks and SUVs between 2005 and 2009. The information listed here is for a stock LS2 truck engine.
Mechanically similar, General Motors’ LS and LS-based Vortec engines wound up on almost every branch of the GM family tree: Chevy, Pontiac, GMC, Cadillac, Buick—heck, even Saab, Hummer, and Isuzu got some LS love.
Since LS and Vortec engines are so common, they’ve become the go-to performance and swap engines of the modern era.
These motors are capable of making a lot of horsepower, and respond well to upgrades like turbos, superchargers, high-flow cylinder heads, intake systems, cams, and nitrous oxide.
The aftermarket is strong, crate engines are available, and used motors are often cheaply sourced through junkyards.
[Do you have an LS2 truck engine you want to upgrade? Read: LS2 Truck Engine Upgrade Guide: Expert Advice for LS2 Truck-Engine Mods to Maximize Performance.]
Summit Racing has created a series of comprehensive guides for each engine in the LS family, so engine builders and tuners can have a handy reference for their projects.
This specific guide is for the GM LS2 engine that was found exclusively in trucks. The LS2 is noteworthy in that it is one of only two LS-series engines (the L76 is the other) that came in both cars and trucks. The respective car and truck versions of the LS2 (and L76) came with different accessory drives, intake manifolds, and oil pans. They also had different VIN codes.
There is a separate guide for the LS2 engine used in GM cars. You can read it here.
Note that LS2 engine specs differ, depending on which vehicle it was in.
For LS2 engines, the 8th digit of the engine/vehicle VIN will be “U” for cars and “H” for trucks.
If that 8th digit is neither a U or H, you probably don’t have an LS2. You can use our handy VIN decoder to find out exactly which LS engine you’ve got.
You can see all of our LS engine spec guides and LS-related information here.
(Summit Racing’s Brian Nutter and Paul Spurlock contributed to this article.)
Chevy LS2 Truck Engine Specs (VIN H)
LS2 (Truck) Performance Specifications
| Engine Ratings | |
|---|---|
| Compression Ratio | 10.9:1 |
| Horsepower Rating | 390-395 hp |
| Torque Rating | 400 ft./lbs. |
LS2 (Truck) Applications
| VIN 8th Digit | Year | Make | Model |
|---|---|---|---|
| H | 2005-06 | Chevy | SSR |
| H | 2006-09 | Chevy | Trailblazer SS |
| H | 2008-09 | Saab | 9-7X Aero |
LS2 (Truck) Engine Blocks
| LS2 (Truck) Block Specs | |
|---|---|
| Casting Numbers | 12568952, 12560799 |
| Material | Aluminum |
| Displacement | 6.0L / 364 c.i.d. |
| Bore Dia. | 4.000 in. |
| Stroke | 3.622 in. |
| Deck Height | 9.240 in. |
| Bore Spacing | 4.400 in. |
| Thrust Bearing Location | #3 Main |
| Main Cap Style | 6-Bolt |
| Main Housing Bore Dia. | 2.751 in. |
| Cam Housing Bore Dia. | Bore 1/5 = 2.346, Bore 2/4 = 2.326, Bore 3 = 2.307 |
| Cam-to-Crank Centerline | 4.914 in. |
LS2 (Truck) Rotating Assembly
| LS2 (Truck) Rotating Assembly Specs | |
|---|---|
| Piston Material | Hypereutectic Cast Aluminum Alloy |
| Piston Style | Flat Top |
| Piston Volume | 0cc |
| Wrist Pin Dia. | 0.9431 in. (full floating) |
| Connecting Rod Material | Powdered Metal |
| Connecting Rod Style | I-Beam |
| Connecting Rod Length | 6.098 in. |
| Connecting Rod Housing Bore | 2.225 in. |
| Connecting Rod Bolts | M9 x 1 x 43 |
| Connecting Rod Part Number | 12649190 |
| Connecting Rod Casting Number | 143 (Last 3 Digits) |
| Crankshaft Material | Cast Iron |
| Crankshaft Part Number | 12569768 |
| Crankshaft Casting Number | 216 (Last 3 Digits) |
| Crankshaft Main Journal | 2.559 in. |
| Crankshaft Rod Journal | 2.100 in. |
| Reluctor Wheel | 24X (2005-06) |
| 58X (2007-09) | |
LS2 (Truck) Cylinder Heads
| LS2 (Truck) Cylinder Head Specs | |
|---|---|
| Casting Numbers | 799, 243 |
| Material | Aluminum |
| Combustion Chamber Volume | 65cc |
| Intake Port Shape | Cathedral |
| Intake Runner Volume | 210cc |
| Exhaust Port Shape | D-Port |
| Exhaust Runner Volume | 75cc |
| Intake Valve Diameter | 2.000 in. |
| Exhaust Valve Diameter | 1.575 in. |
| Cylinder Head Bolt Style | Torque to Yield (TTY) |
| Cylinder Head Bolt Size | (10) M11 x 2 x 100, (5) M8 x 1.25 x 45 |
LS2 (Truck) Cam Specifications
| Applications | 2005-06 | 2007-09 |
|---|---|---|
| Camshaft Part Number | 12574519 | 12593206 |
| Duration @ .050 in. (int./exh.) | 204°/213° | 204°/211° |
| Valve Lift (int./exh.) | 0.520 in./0.521 in. | 0.524 in./0.524 in. |
| Lobe Separation | 116° | 117° |
| Cam Gear Attachment | 3-Bolt | 1-Bolt |
| Cam Gear Poles | 1x | 4x |
| Active Fuel Management (AFM) | No | No |
| Variable Valve Timing (VVT) | No | No |
LS2 (Truck) Valvetrain
| LS2 (Truck) Valvetrain Specs | |
|---|---|
| Lifter Style | Hydraulic Roller |
| Lifter Link Style | Plastic Lifter Tray |
| Lifter Body Diameter | 0.842 in. |
| Pushrod Length | 7.385 in. |
| Rocker Arm Mounting Style | Pedestal |
| Rocker Arm Style | Die-Cast, Roller Fulcrum |
| Rocker Ratio | 1.7 |
| Rocker Offset | None |
| Valve Spring Style | Beehive |
| Valve Spring Color | Natural |
| Valve Angle | 15 Degrees |
| Intake Valve Material | Steel - Solid Stem |
| Intake Valve Dia. | 2.000 in. |
| Exhaust Valve Material | Steel - Solid Stem |
| Exhaust Valve Dia. | 1.575 in. |
| Timing Chain Guide Style | Plastic Guide (2005-06) |
| Spring Loaded Tensioner (2007-09) | |
Other Key LS2 (Truck) Specs
| Throttle Body, Fuel Injectors, Oil Pan Specs & More | ||
|---|---|---|
| Years | 2005-06 | 2007-09 |
| Intake Manifold | Truck-Style | Truck-Style |
| Throttle Body | 87mm, 4-bolt, silver blade | 87mm, 4-bolt, silver blade (Gold blade in 2009 only) |
| Throttle Control | Electronic, Drive-by-Wire | Electronic, Drive-by-Wire |
| Fuel Injector Part Number | 12569113 | 89017586 |
| Fuel Injector Flow | 34 lb./hr. @ 58 psi | 34 lb./hr. @ 58 psi |
| Flex Fuel Capable (E-85) | No | No |
| Fuel Injector Length (between O-Rings) | 2.050 in. | 2.050 in. |
| Fuel Injector Connector | EV6-USCAR | EV6-USCAR |
| Computer | E40 | E67 |
| Crankshaft Reluctor Ring | 24X | 58X |
| Camshaft Sensor Location | Timing Cover | Timing Cover |
| Oil Pan | Varies By Model | Varies By Model |
| Oil Pump | Standard Volume (.96 c.i. per rev.) | Standard Volume (.96 c.i. per rev.) |
…
NOTE: You can find engine specs and detailed engine upgrade advice for every LS and LS-based Vortec truck engine in one place: The Definitive Guide to LS Engine Specs and LS Engine Upgrades.
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Great things to know thanks
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What all do I need to swap a running low mileage 2006 LS2 for a 2003 LQ4 in a 2003 GMC Sierra 1500HD?
Do you have a transmission guide?
I have a Chevy 6L gas engine in my 2014 HD 2500. I had dual exhaust added hoping it will breath better but, I can’t feel any difference. My truck is still like new yet as only has about 45,000 kms. (Yes, I’m a Canadian!) I like to pull my 9K lb. tandem axel trailer with my Chevy 6L but it really suck holes (seriously underpowered) …. especially when climbing in the mountains (I live just 90 miles east). I’m wanting to increase the HP & tq. by about 100 hp & 100tq, but, I don’t want to turn my truck into a “burned out problematic “has been” because apart from the power shortage, it’s been a terrific truck and has never been in for commercial servicing..
What would you suggest as I want to keep the truck for many years yet as apart from the power shortage, it’s a joy to drive, Many thanks!!