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
|Compression Ratio (2007-09)||9.9:1|
|Compression Ratio (2010-14)||9.6:1|
|Horsepower Rating||310-326 hp|
|Torque Rating||335-348 ft./lbs.|
|VIN 8th Digit||Year||Make||Model|
LMG Engine Blocks
|LMG Engine Block Specs|
|Casting Numbers||12576177, 12576178, 1589779|
|Displacement||5.3L / 325 c.i.d.|
|Bore Dia.||3.780 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.|
LMG Rotating Assembly
|LMG Rotating Assembly Specs|
|Piston Material||Hypereutectic 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 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 Casting Number (last 3 digits)||143|
|Crankshaft Material||Cast Iron|
|Crankshaft Casting Number (last 3 digits)||216|
|Crankshaft Main Journal||2.559 in.|
|Crankshaft Rod Journal||2.100 in.|
LMG Cylinder Heads
|LMG Cylinder Head Specs|
|Casting Numbers||799, 243|
|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|
LMG Camshaft Specifications
|LMG Camshaft Specifications|
|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.|
|Cam Gear Attachment||1-Bolt||1-Bolt|
|Cam Gear Poles||4x||4x|
|Active Fuel Management (AFM)||Yes||Yes|
|Variable Valve Timing (VVT)||No||Yes|
|LMG 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|
|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.|
Other Key LMG Specs
|Throttle Body, Fuel Injectors, Oil Pan Specs & More|
|Throttle Body||87mm, 4-bolt|
|Throttle Control||Electronic (Drive-by-Wire)|
|Fuel Injector Part Number||12613411|
|Fuel Injector Flow||32 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 Connector||EV6|
|Crankshaft Reluctor Ring||58x|
|Camshaft Sensor Location||Front mount, 4x on cam|
|Oil Pan||Deep rear sump|
|Oil Pump||Standard 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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