Engine Guides / LS Engines

LMG 5.3L Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More

The LMG engine is a 5.3L Gen. IV iron-block engine used in GM trucks and SUVs between 2007 and 2014. For marketing purposes, it was also known as the Vortec 5300. The information listed here is for a stock LMG 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.

[Looking to upgrade your LMG engine? Check out LMG 5.3L Engine Upgrade Guide: Expert Advice for LMG Mods to Maximize Performance.]

The aftermarket is strong, crate engines are available, and used motors are often cheaply sourced through junkyards.

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 LMG 5.3L Vortec 5300.

You can find more LS engine spec guides and LS-related information here.

(Summit Racing’s Paul Spurlock and Brian Nutter contributed to this article.)

LMG 5.3L Vortec 5300 Engine Specs

LMG Performance Specifications

Engine Ratings
Compression Ratio (2007-09)9.9:1
Compression Ratio (2010-14)9.6:1
Horsepower Rating310-326 hp
Torque Rating335-348 ft./lbs.

LMG Applications

VIN 8th DigitYearMakeModel

LMG Engine Blocks

LMG Engine Block Specs
Casting Numbers12576177, 12576178, 1589779
Displacement5.3L / 325 c.i.d.
Bore Dia. 3.780 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.

LMG Rotating Assembly

LMG Rotating Assembly Specs
Piston MaterialHypereutectic Cast Aluminum Alloy
Piston Style (2007-09)Flat Top
Piston Style (2010-14)Flat Top with Valve Reliefs
Piston Volume (2007-09)0cc
Piston Volume (2010-14)+3cc
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 Casting Number (last 3 digits)143
Crankshaft MaterialCast Iron
Crankshaft Casting Number (last 3 digits)216
Crankshaft Main Journal2.559 in.
Crankshaft Rod Journal2.100 in.
Reluctor Wheel58x

LMG Cylinder Heads

LMG 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

LMG Camshaft Specifications

LMG Camshaft Specifications
Part Number1259320712625436
Duration @ .050 in. (int./exh.)193°/193°196°/201°
Valve Lift (int./exh.)0.482 in./0.482 in.0.481 in./0.481 in.
Lobe Separation116°116°+2
Cam Gear Attachment1-Bolt1-Bolt
Cam Gear Poles4x4x
Active Fuel Management (AFM) YesYes
Variable Valve Timing (VVT)NoYes

LMG Valvetrain

LMG 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.

Other Key LMG Specs

Throttle Body, Fuel Injectors, Oil Pan Specs & More
Intake ManifoldTruck-Style
Throttle Body87mm, 4-bolt
Throttle ControlElectronic (Drive-by-Wire)
Fuel Injector Part Number12613411
Fuel Injector Flow32 lb./hr. @ 43psi; 36 lb./hr. @ 58 psi
Flex Fuel Capable (E-85)Yes
Fuel Injector Length (between O-Rings)1.900 in.
Fuel Injector ConnectorEV6
Crankshaft Reluctor Ring58x
Camshaft Sensor LocationFront mount, 4x on cam
Oil PanDeep rear sump
Oil PumpStandard flow (0.96 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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  1. Pingback: LMG 5.3L Engine Upgrade Guide: Expert Advice for LMG Mods to Maximize Performance - OnAllCylinders

  2. What are some performance upgrade bolt on part numbers that I can purchase for more torque etc

  3. Price Wilson says:

    LMG vs LC9
    LMG vs L33

  4. Pingback: LMF 5.3L Engine Upgrade Guide: Expert Advice for LMF Mods to Maximize Performance - OnAllCylinders

  5. Pingback: Mailbag: Choosing an Engine Management System for an LS-Swapped '82 Olds Cutlass

  6. Michael Piccolo says:

    I own 2007 chevy Silverado with 5.3 L motor. Put K&N filter, single dump 3” exhaust, new plugs and wires, and performance tune by Collingdale speed shop. It completely changed truck for the better. Total cost $1600 I smile every time I floor it.

  7. Will a 2011 5.3 Yukon engine work on a 2007 Suburban

  8. Yacob Hickman says:

    What is the weight of the crankshaft hanging on a linear weight scale.

    What is the weight of the threaded hanger before threaded into the crankshaft harmonic bolt hole.

    What is the weight of the camshaft hanging on a linear weight scale.

    What is the compressed force in inch pounds and foot pounds of intake and exhaust valve springs compressed.

    What is the friction of the crankshaft in the block caped and torqued to spec for the crankshaft only turned , with assembly lube.

    What is the friction of the piston rings on the piston and connecting rod pulled through the cylinder .

    What is the friction of the rear main seal on the crankshaft only, to turn the crankshaft only.

    What is the vacuum for the vacuum stroke when the Piston reached bottom dead center for the compression stroke with compression stroke ratio to aquire 150 psi compression on the compression stroke at top dead center.

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