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To properly install your LS Cylinder Heads, follow the steps below. This will prevent oil and coolant leaks and a loss of compression from a blown head gasket.

**If you use aftermarket bolts or studs, follow the instructions that came with your new fasteners.**

Pre-Installation

Before installing your heads, ensure the following:

  • The bolt holes in the block are clean and the threads are not damaged.
  • The valves, seals, and springs are properly installed.
  • The freeze plugs are installed.
  • The coolant temperature sensor is installed in the driver’s side head.
  • The coolant passage plug is installed on the passenger’s side head.
  • The block is secured to the engine stand.
    • It may rotate with the added weight of the cylinder head.

Installation Process

  1. Press new Dowel Pins into the engine block.
    1. There are 2 dowels per side (in holes #7 and #8).
    2. They align the head to the block. Always replace them before installing your cylinder heads.
    3. If needed, lightly tap them in with a hammer.
  2. Clean the deck surface of the block with a clean rag and acetone (or a similar cleaner).
  3. Place the Head Gasket on the block.
    1. Make sure “front” or “this side up” is facing the appropriate direction.
  4. Clean the deck surface of the head with a clean rag and acetone (or a similar cleaner).
  5. Gently set the cylinder head on top of the head gasket.
    1. Be sure it sits properly on the dowels.
    2. Take care not to nick or scratch the deck surface of the head.
  6. Install all the bolts finger-tight.
  7. Torque the M11 bolts (#1-10) in 3 passes.
    1. See below for torque specs and sequence.
    2. Use a quality Torque Wrench and Torque Angle Gauge.
  8. Torque the M8 bolts (#11-15) in 1 pass.
    1. See below for torque specs and sequence.
  9. Repeat this process for the other cylinder head.

LS Cylinder Head Torque Sequence

LS Cylinder Head Torque Specs
Engine Family Bolt Size First Pass Second Pass Final Pass
Gen. 3 (LS1, LS6, etc.) M11 x 155.5mm 22 ft.-lbs. 90 degrees 90 degrees
M11 x 101mm 50 degrees
M8 x 46mm - - 22 ft.-lbs.
Gen. 4 (LS2, LS3, etc.) M11 x 155.5mm 22 ft.-lbs. 90 degrees 70 degrees
M8 x 46mm - - 22 ft.-lbs.

Notes

  • Stock-style cylinder head bolts are Torque to Yield Fasteners.
    • NEVER reuse old TTY bolts.
  • 2003 and earlier blocks use 155.5mm long bolts in holes #1-8 and 101mm long bolts in holes #9-10.
    • The final torque angle is different. Make sure you use the right specs!
  • For engines that use M12 head bolts, like the LSA and LS9, refer to your GM service manual.
Related Products: Cylinder Heads