Home › Guides › LS engine torque specs: heads, mains, rods, balancer and more
LS engine torque specs: heads, mains, rods, balancer and more
Torque specs for Gen III and Gen IV LS engines, grouped by job: heads, bottom end, front cover, oiling, flywheel, intake, exhaust, sensors and accessories. Multi-pass and torque-angle steps are spelled out, single-use bolts are marked, and every number shows whether our sources agree.
Before you turn a wrench
- Always check the factory service manual for your exact engine and year. GM changed bolts, angles and sequences during production.
- Disconnect the battery before working on the engine or wiring.
- Torque-to-yield bolts (head bolts, the balancer bolt) stretch when tightened. They are single use: install new ones.
- Clean threads, the right lube (or none, as the manual says) and a calibrated torque wrench matter as much as the number.
How to read it: "Gen III" is 1997–2003 (LS1, LS6, LM7, LQ4, LQ9, LR4 and friends). The Gen IV column only shows a number when it differs. ft-lb = foot-pounds, in-lb = inch-pounds (12 in-lb = 1 ft-lb). "→" means the next pass; "+90°" means turn a further 90 degrees with an angle gauge.
Cylinder heads
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Head bolts, M11 (long and medium), 1997 to early-2004 heads Use a torque-angle gauge. Clean, dry block threads unless your manual says to oil them. The two bolt designs are not interchangeable. | 22 ft-lb all M11 in sequence → +90° all M11 in sequence → final +90° on the long bolts, +50° on the medium-length bolts at the front and rear of each head | Mid-2004 and later (all M11 the same length): 22 ft-lb → +90° → +70° | Yes (torque-to-yield) | 2+ sources agree |
| Head bolts, M8 (top row) | 22 ft-lb, in sequence, after the M11 bolts | Same | Yes (torque-to-yield) | 2+ sources agree |
| Rocker arm bolts Turn the crank so each lifter is on the base circle before you torque its rocker. | 22 ft-lb | Same | No | 2+ sources agree |
| Valve cover bolts | 106 in-lb | Same | No | 2+ sources agree |
| Coil bracket to valve cover / coil to bracket | 106 in-lb | Same | No | One source: verify |
| Spark plugs Aluminum heads: start every plug by hand. | 15 ft-lb in new heads; 11 ft-lb when re-installing in used heads | Same | No | One source: verify |
| Cylinder head coolant plug and core-hole plug | 15 ft-lb | Same | No | One source: verify |
| Lifter guide (tray) bolts Sources differ: 106 in-lb in the 2000 F-body service table, 89 in-lb in a Gen III/IV list. Check your manual. | 106 in-lb | Same | No | Sources differ |
Bottom end
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Main cap inner bolts Angle-torqued. Builders usually upgrade to ARP studs and use ARP's spec. | 15 ft-lb in sequence → +80° in sequence | Same | Check your manual | 2+ sources agree |
| Main cap outer studs Sources differ: 53° (Gen III data) vs 51° (Gen IV data). Use the number in the manual for your block. | 15 ft-lb in sequence → +53° in sequence | Iron and aluminum Gen IV lists give +51° | Check your manual | Sources differ |
| Main cap side bolts Tighten after the inner bolts and outer studs. | 18 ft-lb | Same | No | 2+ sources agree |
| Connecting rod bolts, first design | 15 ft-lb → +60° | Same | Check your manual | 2+ sources agree |
| Connecting rod bolts, second design Sources differ: 75° in the 2000 F-body service table, 85° in other Gen III and Gen IV lists. Identify your rod bolt and use your manual's number, or ARP's spec for ARP bolts. | 15 ft-lb → +75° | Gen IV lists: 15 ft-lb → +85° | Check your manual | Sources differ |
| Crankshaft oil deflector (windage tray) nuts | 18 ft-lb | Same | No | 2+ sources agree |
Front of engine
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Crank balancer bolt Lock the flywheel or flexplate. The old bolt is only for pressing the balancer on. An ARP bolt is reusable and uses ARP's spec. | Seat the balancer with an installer tool or the OLD bolt to 240 ft-lb, then remove it. Install a NEW bolt: 37 ft-lb → +140° | One Gen IV list shows a different procedure (111 ft-lb, loosen, then 59 ft-lb). Check your manual. | Yes (new bolt every time) | 2+ sources agree |
| Camshaft retainer (thrust) plate bolts Use medium-strength thread locker. | 18 ft-lb | Countersunk-screw plates: 11 ft-lb | No | 2+ sources agree |
| Cam gear bolts, 3-bolt cams Most sources give 26 ft-lb; one Gen IV list says 22 ft-lb. Use medium-strength thread locker. | 26 ft-lb | One Gen IV list gives 22 ft-lb | No | Sources differ |
| Cam gear bolt, single-bolt (VVT and later Gen IV) Gen IV only. | Not used on Gen III | 55 ft-lb → +50° | Check your manual | 2+ sources agree |
| Front (timing) cover bolts Center the cover on the crank snout (an alignment tool or the balancer) before final torque. | 18 ft-lb | Same | No | 2+ sources agree |
| Rear cover bolts | 18 ft-lb | Same | No | 2+ sources agree |
| Valley cover bolts | 18 ft-lb | Same | No | 2+ sources agree |
| Water pump bolts Two passes. | 11 ft-lb all → 22 ft-lb all | Same | No | 2+ sources agree |
| Water inlet (thermostat) housing bolts | 11 ft-lb | Same | No | 2+ sources agree |
| Water pump cover bolts | 11 ft-lb | Same | No | One source: verify |
Oiling
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Oil pump to block bolts Center the pump on the crank before tightening. | 18 ft-lb | Same | No | 2+ sources agree |
| Oil pump cover bolts | 106 in-lb | Same | No | One source: verify |
| Oil pump relief valve plug | 106 in-lb | Same | No | One source: verify |
| Pickup tube to oil pump bolt Small bolt; it strips easily. New O-ring on the pickup every time. | 106 in-lb | Same | No | 2+ sources agree |
| Pickup tube nuts (to main cap studs) | 18 ft-lb | Same | No | One source: verify |
Oil pan
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Oil pan M8 bolts (pan to block and pan to front cover) | 18 ft-lb | Same | No | 2+ sources agree |
| Oil pan M6 bolts (pan to rear cover) Going past this snaps the small bolts. | 106 in-lb | Same | No | 2+ sources agree |
| Oil pan drain plug | 18 ft-lb | Same | No | 2+ sources agree |
| Oil pan baffle, cover and closeout cover bolts | 106 in-lb | Same | No | One source: verify |
| Oil filter | 22 ft-lb | Same | No | One source: verify |
| Oil filter fitting (adapter) | 40 ft-lb | Same | No | One source: verify |
| Oil level sensor | 115 in-lb | Same | No | One source: verify |
Flywheel & transmission
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Flywheel or flexplate bolts Three passes in a star pattern. ARP bolts use ARP's spec. | 15 ft-lb → 37 ft-lb → 74 ft-lb | Same | No | 2+ sources agree |
| Flexplate to torque converter bolts | 44 ft-lb | Same | No | One source: verify |
| Transmission to engine bolts | 37 ft-lb | Same | No | 2+ sources agree |
Intake & fuel
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Intake manifold bolts Plastic manifolds crack if over-tightened. Use new port gaskets. | 44 in-lb in sequence → 89 in-lb in sequence | Same | No | 2+ sources agree |
| Fuel rail bolts | 89 in-lb | Same | No | One source: verify |
| Throttle body bolts Sources differ: 106 in-lb in the 2000 F-body service table, 89 in-lb in a Gen III/IV list. | 106 in-lb | Same | No | Sources differ |
Exhaust
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Exhaust manifold or header bolts Two passes, center bolts out. Header makers may give their own number. | 11 ft-lb → 18 ft-lb | One Gen IV list gives 15 ft-lb final | No | 2+ sources agree |
| Exhaust manifold to pipe nuts | 26 ft-lb | Same | No | One source: verify |
| Catalytic converter nuts | 18 ft-lb | Same | No | One source: verify |
| AIR pipe to exhaust manifold bolts | 15 ft-lb | Same | No | One source: verify |
| Oxygen sensors Use anti-seize made for O2 sensors on the threads only. | 31 ft-lb | Same | No | One source: verify |
Sensors
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Knock sensors Gen III sensors sit in the valley under the intake; Gen IV moved them to the sides of the block. | 15 ft-lb | Same | No | One source: verify |
| Crank position sensor bolt | 18 ft-lb | Same | No | 2+ sources agree |
| Cam position sensor bolt Different location by generation, so a different spec. | 18 ft-lb (Gen III sensor, back of the block) | 106 in-lb (Gen IV sensor, in the front cover) | No | 2+ sources agree |
| Coolant temperature sensor | 15 ft-lb | Same | No | 2+ sources agree |
| Oil pressure sensor | 15 ft-lb | Same | No | One source: verify |
Block
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Block coolant drain plugs and oil gallery plugs Use sealant on gallery plugs. | 44 ft-lb | Same | No | One source: verify |
| Block heater | 30 ft-lb | Same | No | One source: verify |
| Ground strap at the rear of the head | 37 ft-lb | Same | No | One source: verify |
| Engine mount to block bolts Swap-kit mounts: use the kit maker's numbers for its own bolts. | 37 ft-lb | Same | No | 2+ sources agree |
Accessories
| Fastener | Gen III spec | Gen IV, if different | Single use? | Checked |
|---|---|---|---|---|
| Drive belt tensioner and idler pulley bolts | 37 ft-lb | Same | No | One source: verify |
| Alternator bracket bolts | 37 ft-lb (rear bracket bolts 18 ft-lb) | Same | No | One source: verify |
| A/C compressor, compressor bracket and A/C idler bolts | 37 ft-lb (A/C tensioner 18 ft-lb) | Same | No | One source: verify |
| Power steering pump and bracket bolts | 18 ft-lb | Same | No | One source: verify |
Single-use (torque-to-yield) bolts
- Cylinder head bolts, both M11 and M8. Buy a new GM set or switch to ARP bolts or studs, which are reusable and use ARP's own torque and lube. Head bolt spec.
- Crank balancer bolt. The old bolt is only for pressing the balancer on; the final bolt is always new. Balancer procedure.
- Main and rod fasteners are angle-torqued. Follow your manual on reuse; most engine builders install new bolts or ARP hardware. Main caps · Rods.
Torque-angle, done right
- Run every bolt in by hand first, then do the first pass (in ft-lb) in the factory sequence.
- Zero an angle gauge on each bolt and turn it the full angle in one smooth pull. Don't stop halfway and restart.
- Do each pass on every bolt in sequence before starting the next pass.
- If a bolt spins without tightening or a thread pulls, stop. Fix the thread before you go on.
How we checked: 60 fasteners. 29 agree across two or more independent sources (GM service data plus at least one separate published list); 5 differ between sources and say so in the row; 26 come from GM service data for the 2000 F-body only and are marked "One source: verify". Where sources disagree we show both numbers rather than pick one.
Doing a cam swap? Follow the F-body cam and valve spring swap guide. Rebuilding? See "Refresh while it's out" on each engine page.
Sources
- Chevrolet LS Gen. 3, Aluminum Block Torque Specs — Summit Racing
- Chevrolet LS Gen. 4 Aluminum Block Torque Specs — Summit Racing
- Chevrolet LS Gen. 4 Iron Block Torque Specs — Summit Racing
- 1992-2006 BMW E36 and E46 LS Engine Mounts - ICT Billet — ICT Billet
- c5corvettes.com — c5corvettes.com
- img.motora.cz — img.motora.cz
- ffperformance.co — ffperformance.co
- poormanmotorsports.com — poormanmotorsports.com
- ssonly.com — ssonly.com
- LS1 torque specs (GM service data, 2000 F-body) — ls1howto.com
- LS torque specs — Ewalt's Auto Tuning
- LS & LT engine torque specs — Michigan Motorsports