Vehicle Applications

• 2005–2008 Pontiac Grand Prix GXP
• 2006–2007 Chevrolet Monte Carlo SS
• 2006–2009 Chevrolet Impala SS
• 2008–2009 Buick Lacrosse Super

Product Highlights

• Gen IV Aluminum Cylinder Block
• Cathedral Port Aluminum Cylinder Heads
• Active Fuel Management (AFM) / Displacement on Demand (DOD)
• Advanced Electronic Throttle Control
• 24X E40 ECM (2005-2007) &  58X E38 ECM (2007-2009) Ignition Systems

LS4 Engine Specs (VIN "C")

It is unique because it was the only LS engine used in FWD vehicles.

To make this engine work, GM made several modifications to the engine:

• The engine was mounted in a transverse position, using unique motor mounts.
• The intake manifold was smaller than other LS manifolds and reversed, placing the throttle body placed over the flexplate.
• The engine used a metric, 60 degree, Chevrolet V6 bellhousing.
• The starter was mounted on the transmission, not the engine block.
• The timing cover, crankshaft, and accessory drive were all modified to fit in the FWD engine bays.

Because of its unique configuration, the LS4 is usually not a good candidate for an engine swap. The information listed here is for a stock engine.

Performance Specifications
Compression Ratio	10 : 1
Horsepower Rating	303 hp.
Torque Rating	323 ft./lbs.

 

Application Information
VIN 8th Digit	Year	Make	Model
C	2005-08	Pontiac	Grand Prix GXP
	2006-07	Chevrolet	Monte Carlo SS
	2006-09		Impala SS
	2008-09	Buick	LaCrosse Super

 

Engine Block Specifications
Casting Number	12569004
Material	Aluminum
Displacement	5.3L / 325 c.i.d.
Bore Dia.	3.780 in.
Stroke	3.622 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 in. Bore 2/4 = 2.326 in. Bore 3 = 2.307 in.
Cam-to-Crank Centerline	4.914 in.

 

Rotating Assembly Specifications
Piston Material	Hypereutectic Cast Aluminum Alloy
Piston Style	Flat Top
Piston Volume	0cc
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 P/N	12649190
Connecting Rod Casting Number (last three digits)	143
Crankshaft Material	Cast Iron
Crankshaft P/N	12568920
Crankshaft Casting Number (last three digits)	216
Crankshaft Main Journal Dia.	2.559 in.
Crankshaft Rod Journal Dia.	2.100 in.
Crankshaft Length	13mm shorter than standard (-10mm snout, -3mm rear flange)
Reluctor Wheel	24X (2005, 2006 and early 2007, 58X (later 2007-09)

 

Cylinder Head Specifications
Casting Numbers	799, 243
Material	Aluminum
Combustion Chamber Volume	65cc
Intake Port Shape	Cathedral
Intake Runner Volume	210cc
Exhaust Port Shape	D-Port
Exhaust Runner Volume	75cc
Intake Valve Dia.	2.000 in.
Exhaust Valve Dia.	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

 

Camshaft Specifications
Years	2005-07	2007-09
Camshaft P/N	12569525	12625436
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 Separation	114°	116°+2
Cam Gear Attachment	3-Bolt	1-Bolt
Cam Gear Poles	1X	4X
Active Fuel Management (AFM)	Yes
Variable Valve Timing (VVT)	No

 

Valvetrain Specifications
Lifter Style	Hydraulic Roller
Lifter Link Style	Plastic Lifter Tray
Lifter Body Dia.	0.842 in.
Pushrod Length	7.385 in.
Rocker Arm Mounting Style	Pedestal
Rocker Arm Style	Die-Cast, Roller Fulcrum
Rocker Ratio	1.7
Rocker Offset	None
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.
Timing Chain Guide Style	Plastic Guide (2005-06), Spring Loaded Tensioner (2007-09)

 

Other Specifications
Intake Manifold P/N	12604786
Intake Manifold	Car-Style (Reversed)
Throttle Body P/N	12568580 (2005-07)	12631016 (2008-09)
Throttle Body	76mm, 4-Bolt, Gold blade (Non-standard bolt pattern)
Throttle Control	Electronic (Drive-by-Wire)
Fuel Injector P/N	12580681
Fuel Injector Flow	30 lb/hr @ 58 psi
Flex Fuel Capable (E-85)	No
Fuel Injector Length (between O-rings)	1.900 in.
Fuel Injector Connector	EV6 / USCAR
Computer	E40 (2005-07)	E67 (2007-09)
Crankshaft Reluctor Ring	24X (2005, 2006. early 2007)	58X (2007-09)
Camshaft Sensor Location	Timing Cover
Oil Pan	Centered Sump
Oil Pump	High Volume (1.25 c.i./rev.)