LS head bolt torque specs and sequence

Stock LS head bolts are torque-to-yield (TTY): you tighten to a torque, then turn each bolt a set number of degrees. Never reuse the old TTY bolts — install new ones.

Summit's aluminum-block and iron-block spec sheets list the same head bolt values within each generation.

Gen III (LS1, LS6, 4.8/5.3/6.0 Vortec through ~2007):

Bolt	First pass	Second pass	Final pass
M11 × 2.0 × 155.5 mm (long)	22 ft-lb	90°	90°
M11 × 2.0 × 101.0 mm (short)	22 ft-lb	90°	50°
M8 × 1.25 × 46.0 mm	—	—	22 ft-lb

Gen IV (LS2, LS3, L92, L76 and later LS):

Bolt	First pass	Second pass	Final pass
M11 × 2.0 × 155.5 mm	22 ft-lb	90°	70°
M8 × 1.25 × 46.0 mm	—	—	22 ft-lb

Sequence: the ten M11 bolts (#1–10) are tightened in the numbered sequence in three passes; the five small M8 bolts (#11–15) are done in one pass. Use the numbered diagram in your GM service manual or head gasket instructions for the exact order.

Before you torque (Summit's install steps):

• Bolt holes in the block clean, threads undamaged.
• New dowel pins pressed into the block — two per side, in holes #7 and #8.
• Block and head deck surfaces cleaned with acetone (or similar) before setting the gasket and head.

Exceptions: the LSA and LS9 use M12 head bolts — use the GM service manual spec for those. With ARP studs/bolts or other aftermarket fasteners, follow that hardware's instructions, not these numbers.

Use an angle gauge for the degree steps rather than estimating.