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 Ratio10.9:1
Horsepower Rating390-395 hp
Torque Rating400 ft./lbs.

LS2 (Truck) Applications

VIN 8th DigitYearMakeModel
H2006-09ChevyTrailblazer SS
H2008-09Saab9-7X Aero

LS2 (Truck) Engine Blocks

LS2 (Truck) Block Specs
Casting Numbers12568952, 12560799
Displacement6.0L / 364 c.i.d.
Bore Dia. 4.000 in.
Stroke3.622 in.
Deck Height9.240 in.
Bore Spacing4.400 in.
Thrust Bearing Location#3 Main
Main Cap Style6-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 Centerline4.914 in.

LS2 (Truck) Rotating Assembly

LS2 (Truck) Rotating Assembly Specs
Piston MaterialHypereutectic Cast Aluminum Alloy
Piston StyleFlat Top
Piston Volume0cc
Wrist Pin Dia.0.9431 in. (full floating)
Connecting Rod MaterialPowdered Metal
Connecting Rod StyleI-Beam
Connecting Rod Length6.098 in.
Connecting Rod Housing Bore2.225 in.
Connecting Rod BoltsM9 x 1 x 43
Connecting Rod Part Number12649190
Rod Casting Number
143 (Last 3 Digits)
Crankshaft MaterialCast Iron
Crankshaft Part Number12569768
Crankshaft Casting Number216 (Last 3 Digits)
Crankshaft Main Journal2.559 in.
Crankshaft Rod Journal2.100 in.
Reluctor Wheel24X (2005-06)
58X (2007-09)

LS2 (Truck) Cylinder Heads

LS2 (Truck) Cylinder Head Specs
Casting Numbers799, 243
Combustion Chamber Volume65cc
Intake Port ShapeCathedral
Intake Runner Volume210cc
Exhaust Port ShapeD-Port
Exhaust Runner Volume75cc
Intake Valve Diameter2.000 in.
Exhaust Valve Diameter1.575 in.
Cylinder Head Bolt StyleTorque to Yield (TTY)
Cylinder Head Bolt Size(10) M11 x 2 x 100, (5) M8 x 1.25 x 45

LS2 (Truck) Cam Specifications

Camshaft Part Number1257451912593206
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 Separation116°117°
Cam Gear Attachment3-Bolt1-Bolt
Cam Gear Poles1x4x
Active Fuel Management (AFM) NoNo
Variable Valve Timing (VVT)NoNo

LS2 (Truck) Valvetrain

LS2 (Truck) Valvetrain Specs
Lifter StyleHydraulic Roller
Lifter Link StylePlastic Lifter Tray
Lifter Body Diameter0.842 in.
Pushrod Length7.385 in.
Rocker Arm Mounting StylePedestal
Rocker Arm StyleDie-Cast, Roller Fulcrum
Rocker Ratio1.7
Rocker OffsetNone
Valve Spring StyleBeehive
Valve Spring ColorNatural
Valve Angle15 Degrees
Intake Valve MaterialSteel - Solid Stem
Intake Valve Dia.2.000 in.
Exhaust Valve MaterialSteel - Solid Stem
Exhaust Valve Dia.1.575 in.
Timing Chain Guide StylePlastic Guide (2005-06)
Spring Loaded Tensioner (2007-09)

Other Key LS2 (Truck) Specs

Throttle Body, Fuel Injectors, Oil Pan Specs & More
Intake ManifoldTruck-StyleTruck-Style
Throttle Body87mm, 4-bolt, silver blade87mm, 4-bolt, silver blade (Gold blade in 2009 only)
Throttle ControlElectronic, Drive-by-WireElectronic, Drive-by-Wire
Fuel Injector Part Number1256911389017586
Fuel Injector Flow34 lb./hr. @ 58 psi34 lb./hr. @ 58 psi
Flex Fuel Capable (E-85)NoNo
Fuel Injector Length (between O-Rings)2.050 in.2.050 in.
Fuel Injector ConnectorEV6-USCAREV6-USCAR
Crankshaft Reluctor Ring24X58X
Camshaft Sensor LocationTiming CoverTiming Cover
Oil PanVaries By ModelVaries By Model
Oil PumpStandard 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.