LS Engines

L76 Car Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More

 
2008 Pontiac G8 GT L76 engine photo by Top Speed

(Image/Top Speed)

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: The L76 appeared in both cars AND trucks, and there are some differences between the two. To read about the L76 truck engine specifically, check out L76 Truck Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More.]

The aftermarket is strong for LS swap engines. 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 guide is specifically about the GM L76 car engine. You can find our other LS engine spec guides and LS-related tech articles here.

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

GM L76 Car Engine Specs

The L76—like its LS2 sibling—is a 6.0L, Gen. 4, aluminum small block engine that was used both in GM cars and trucks. The L76 is an adapted version of the LS2, featuring new rectangle port cylinder heads and Active Fuel Management (AFM).

The L76 was available in the Pontiac G8 GT from 2007-09. It was also used in some Australian Holden cars.

(NOTE: Don’t confuse the engine specs here with the L-76 5.4L small block which could be found in the C2 Sting Ray Corvette in 1964.)

The information listed below is for the stock engine.

L76 (Car) Performance Specifications

Engine Ratings
Compression Ratio10.4:1
Horsepower Rating355 hp
Torque Rating384 ft./lbs.

L76 (Car) Applications

VIN 8th DigitYearMakeModel
Y2007-09PontiacG8 GT
N/A2006HoldenCommodore VZ Series II
N/A2009-10HoldenCommodore VE Series I
Note: The Australian vehicles use a different format for Vehicle Identification Numbers (VIN). The 8th digit is NOT the engine code in an Australian VIN code.

L76 (Car) Engine Blocks

L76 (Car) Block Specs
Casting Numbers12568952
MaterialAluminum
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.

L76 (Car) Rotating Assembly

L76 (Car) 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
Crankshaft MaterialCast Iron
Crankshaft Part Number12588613
Crankshaft Main Journal2.559 in.
Crankshaft Rod Journal2.100 in.
Reluctor Wheel58x

L76 (Car) Cylinder Heads

L76 (Car) Cylinder Head Specs
Casting Numbers5364, 823
MaterialAluminum
Combustion Chamber Volume70cc
Intake Port ShapeRectangle
Intake Runner Volume257cc
Exhaust Port ShapeD-Port
Exhaust Runner Volume87cc
Intake Valve Diameter2.165 in.
Exhaust Valve Diameter1.590 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

L76 (Car) Camshaft

L76 (Car) Cam Specifications
Camshaft Part Number12625439
Duration @ .050 in. (int./exh.)196°/208°
Valve Lift (int./exh.)0.478 in./0.466 in.
Lobe Separation116°
Cam Gear Attachment1-Bolt
Cam Gear Poles4x
Active Fuel Management (AFM)Yes, on the Pontiac G8 GT and the 2009-10 Commodore with an automatic transmission
Active Fuel Management (AFM)No, on the 2006 Commodore and the 2009-10 Commodore with a manual transmission
Variable Valve Timing (VVT)No

L76 (Car) Valvetrain

L76 (Car) 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 OffsetOffset Intake
Valve Spring StyleBeehive
Valve Spring ColorNatural
Valve Angle15 Degrees
Intake Valve MaterialSteel - Solid Stem
Intake Valve Dia.2.165 in.
Exhaust Valve MaterialSteel - Solid Stem
Exhaust Valve Dia.1.590 in.

Other Key L76 (Car) Specs

Throttle Body, Fuel Injectors, Oil Pan Specs & More
Intake ManifoldCar-Style
Throttle Body90mm, 4-bolt
Throttle ControlElectronic (Drive-by-Wire)
Fuel Injector Part Number12576341
Fuel Injector Flow42 lb./hr. @ 58 psi
Flex Fuel Capable (E-85)No
Fuel Injector Length (between O-Rings)1.500 in.
Fuel Injector ConnectorEV6-USCAR
ComputerE38
Crankshaft Reluctor Ring58x
Camshaft Sensor LocationFront Timing Cover, 4x
Oil PanVaries By Model
Oil PumpHigh Volume (1.26 c.i. per rev. @ 33 psi)
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