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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