The LS9 is a Gen. 4, 6.2L, aluminum small block engine used in GM cars between 2009 and 2013. The information listed here is for a stock LS9 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.

[NOTE: Looking to upgrade your LS9? Read: LS9 6.2L Engine Upgrade Guide: Expert Advice for LS9 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 LS9 6.2L engine.

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.)

LS9 6.2L Engine Specs

LS9 Performance Specifications

Engine Ratings
Compression Ratio9.1:1
Horsepower Rating638 hp @ 6,300 rpm
Torque Rating604 ft./lbs.
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LS9 Engine Blocks

LS9 Engine Block Specs
Casting Numbers12621766
Material319-T7 Aluminum
Displacement6.2L / 376 c.i.d.
Bore Dia. 4.065 in.
Stroke3.622 in.
Deck Height9.240 in.
Bore Spacing4.400 in.
Thrust Bearing Location#3 Main
Main Cap Style6-Bolt, Billet Steel
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.
Head BoltsM12

LS9 Rotating Assembly

LS9 Rotating Assembly Specs
Piston MaterialHypereutectic Cast Aluminum Alloy
Piston Part Number19180414
Piston StyleDished; No Relief Valves
Piston Volume+15cc
Wrist Pin Dia.0.984 in.
Connecting Rod Part Number12624231
Connecting Rod MaterialTitanium, Moly-Coated
Connecting Rod Weight452-482g
Connecting Rod StyleI-Beam
Connecting Rod Length5.990 in.
Connecting Rod Housing Bore2.225 in.
Connecting Rod BoltsM9 x 1 x 40
Crankshaft MaterialForged Steel, 46MnVS
Crankshaft Part Number12598610 (2009-11), 12641693 (2011-15)
Crankshaft Rear Flange9-Bolt
Crankshaft SnoutLong, with keyway
Crankshaft Main Journal2.559 in.
Crankshaft Rod Journal2.100 in.
Reluctor Wheel58x

LS9 Cylinder Heads

LS9 Cylinder Head Specs
Cylinder Head Part Number12621773
Casting Numbers1771
Material356-T6 Rotocast Aluminum
Combustion Chamber Volume69.8cc
Intake Port ShapeRectangle
Intake Runner Volume259cc
Exhaust Port ShapeD-Port
Exhaust Runner Volume89cc
Valve Seat Material (int./ext.)PMF28 / Brico 3220
Cylinder Head Bolt StyleTorque to Yield (TTY)
Cylinder Head Bolt Size(10) M12 x 2 x 100, (5) M8 x 1.25 x 45
Head Gasket Part Number12622033
Head Gasket Compressed Thickness0.055 in.

LS9 Camshaft Specifications

LS9 Camshaft Specifications
Camshaft Part Number126384277
Duration @ .050 in. (int./exh.)211°/230°
Valve Lift (int./exh.)0.562 in./0.558 in.
Lobe Separation122.5°
Cam Gear Attachment3-Bolt
Cam Gear Poles4x
Active Fuel Management (AFM) No
Variable Valve Timing (VVT)No

LS9 Valvetrain

LS9 Valvetrain Specs
Lifter StyleHydraulic Roller
Lifter Link StylePlastic Lifter Tray
Lifter Body Diameter0.842 in.
Pushrod Length7.385 in.
Pushrod Diameter0.3125 in.
Rocker Arm Mounting StylePedestal
Rocker Arm StyleDie-Cast, Roller Fulcrum
Rocker Ratio1.7
Rocker OffsetIntake only
Valve Spring StyleBeehive
Valve Spring Seat Pressure90 lbs. @ 1.800 in.
Valve Spring Spring Open Pressure295 lbs. @ 1.250 in.
Valve Spring ColorNatural
Valve Angle15 Degrees
Intake Valve MaterialTitanium, with Chrome Nitride
Intake Valve Dia.2.165 in.
Exhaust Valve MaterialStainless steel, Sodium Filled
Exhaust Valve Dia.1.590 in.
Timing Chain Part Number12646386
Timing Chain Guide StyleWedge Shaped Plastic Dampener

LS9 Supercharger Specifications

Supercharger Part Number19244103 (solid coupler) R2300
Supercharger Drive2.32 drive ratio, 15,080 rpm, 9.4 lbs. boost
Rotor Dimensions4.400 diameter, 8.300 length, 160 degree
Pulley Diameter3.100 in. upper / 7.330 in. lower

Other Key LS9 Specs

Throttle Body, Fuel Injectors, Oil Pan Specs & More
Intake ManifoldCast Aluminum, with integrated intercooler
Throttle Body87mm
Throttle ControlElectronic (Drive-by-Wire)
Fuel Injector Part Number12598646
Fuel Injector Flow59 lb./hr. @ 58 psi
Flex Fuel Capable (E-85)No
Fuel Injector Length (between O-Rings)1.500 in.
Fuel Injector ConnectorEV6-USCAR
Camshaft Sensor LocationTiming Cover
Oiling SystemDry Sump
Oil PanCenter Sump (with a bolt-on cooler)
Oil Pump Part Number12578147
Oil Pump Volume32.3 gpm
Engine Weight (with Manifolds, supercharger, Clutch, Flywheel, Balancer, Waterpump531 lbs.

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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