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LH6

LH6 Vortec 5.3L V8 "GEN IV"

Vehicle Applications

  • 2005-2009 Chevrolet Trailblazer including EXT (through 2006)
  • 2005-2009 GMC Envoy Denali
  • 2005-2006 GMC Envoy XL
  • 2005 GMC Envoy XUV
  • 2005-2007 Buick Rainier
  • 2005-2009 Saab 9-7X
  • 2005-2007 Isuzu Ascender
  • 2007 Chevrolet Silverado 1500
  • 2007-2009 GMC Sierra 1500

Product Highlights

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

LH6 Engine Specs (VIN "M")

The information listed here is for a stock engine.

Performance Specifications
Compression Ratio 9.9 : 1
Horsepower Rating 302-315 hp.
Torque Rating 330-338 ft./lbs.

 

Application Information

VIN 8th Digit

Year

Make

Model

M

2005-06

Chevrolet

Trailblazer EXT

GMC

Envoy XL, XUV

Isuzu

Ascender

2005-07

Buick

Rainier

2005-09

GMC

Envoy Denali

Saab

9-7X 5.3i, ARC

2006-08

Chevrolet

Trailblazer

2007-09

Chevrolet

Silverado 1500

GMC

Sierra 1500

 

Engine Block Specifications
Casting Numbers

125771048, 12601900, 12569513, 12568573

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 Part Number

12649190
Connecting Rod Casting Number (last three digits)

143
Crankshaft Material

Cast Iron
Crankshaft Part Number

12574522
Crankshaft Casting Number (last three digits)

216
Crankshaft Main Journal Dia.

2.559 in.
Crankshaft Rod Journal Dia.

2.100 in.
Reluctor Wheel

24X (2005-06), 58X (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

2005-06

2007-09
Part Number

12569525

12625436
Duration @ .050 in. (int./exh.)

Not Available

196°/201°
Valve Lift (int./exh.)

Not Available

0.481 in./0.481 in.
Lobe Separation

Not Available

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

Truck-Style
Throttle Body

87mm, 4-bolt
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 (2005-06), E38 (2007-09)
Crankshaft Reluctor Ring

24X (2005-06), 58X (2007-09)
Camshaft Sensor Location

Timing Cover
Oil Pan

Varies by Application
Oil Pump

High Volume (1.25 c.i./rev.)


LH6 Harnesses