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6.2L LS3 V8 · Cylinder Head

Cylinder head bolts, M11

Torque-to-yield. This fastener is tightened past its elastic limit and permanently stretches. Always install a new one — a reused TTY bolt will not clamp to spec.

Tightening procedure

  1. Torque 22 lb-ft · 30 N·m
  2. Angle 90°
  3. Angle 70°

Complete the passes in the order shown. Angle passes are turn-of-the-nut steps measured with an angle gauge after the preceding torque pass.

Sequence note

Tightened in the numbered published sequence (broadly center-outward), positions 1-10. The LS3 is a mid-2004-and-later 'second-design' (short-head-bolt-style) block, so all ten M11 bolts are the same length, 100 mm; the 8-long-plus-2-short mix (155 mm in holes 1-8, 100 mm in 9-10) belongs to the early 'first-design' / pre-2004 block only.

Tools

  • socket
  • angle gauge

Notes

Torque-to-yield; do not reuse. LS3 (Gen IV) sequence: 22 lb-ft, then 90 deg, then 70 deg (GM SI 2296270). Bolt length 100 mm for all ten M11 holes: the LS3 is a mid-2004-and-later 'second-design' (short-head-bolt-style) block, which uses ten uniform M11 x 2.0 x 100 mm bolts. Backed by the GM part numbers - head-bolt set PN 17800568 (2004+), individual short bolt PN 19258707 listed as 'M11 x 2 x 100'. The 155 mm long bolt (GM PN 11588291) and the 8x155 + 2x100 mix belong to the early 'first-design' / pre-2004 block (GM set PN 12498545); Mike Mavrigian's 'Building the Chevy LS Engine' likewise attributes 100 mm to Gen IV LS2/LS3/LS7. GM SI publishes no bolt length, so this comes from the GM part numbers. A Summit reference (SR-05187) had instead listed 155.5 mm for Gen 4, which appears to be the first-design long-bolt length carried over in error; length corrected 155.5 -> 100 mm on 2026-06-04. The early Gen III (LS1/LS6, C5 Corvette) head-bolt sequence was moved to content/ls1/fastener-specs.json on 2026-06-03. Socket: not separately specified by GM. The M11 head bolts have a reduced 6-point head; community reports conflict (1/2 inch vs ~15mm), so the socket is left unspecified pending confirmation. Thread engagement (GM thread-repair doc 2055312): the M11 x 2.0 head-bolt hole is listed at 60.0 mm (2.36 in) max tap depth, so ~60 mm of the bolt threads into the block. With the 100 mm bolt that leaves ~40 mm spanning the cylinder head, consistent with the short 2nd-design length and ruling out the 155 mm 1st-design bolt.

Sources

  • GM Fastener Tightening Specifications (6.2L LS3), Document ID 2296270

Values are cited as facts. We do not reproduce the manufacturer's prose, table layout, or diagrams.