Torque Spec Reference
Common torque specs for lug nuts, engine fasteners, brakes, and general hardware. Always verify with an OEM service manual for final assembly.
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Small Block Chevy (265–400 ci)
| Fastener | ft-lb | Nm |
|---|---|---|
Cylinder head boltscritical 3-pass sequence: 25 → 45 → 65 ft-lb. ARP studs: ~75–80 ft-lb with ARP lube. | 65 | 88 |
Main bearing cap bolts — 2-boltcritical | 70 | 95 |
Main bearing cap bolts — 4-bolt innercritical | 70 | 95 |
Main bearing cap bolts — 4-bolt outercritical | 65 | 88 |
Connecting rod bolts (3/8" OEM)critical | 45 | 61 |
Intake manifold bolts Tighten in sequence, center outward. | 30 | 41 |
Exhaust manifold bolts | 20 | 27 |
Harmonic balancer bolt | 60 | 81 |
Flywheel / flexplate bolts | 60 | 81 |
Valve cover bolts25 in-lb Overtightening cracks covers. | 2.1 | 3 |
Oil pan bolts (1/4"–20)65 in-lb | 5.4 | 7 |
Oil pan bolts (5/16"–18) | 13 | 18 |
Water pump bolts | 30 | 41 |
Spark plugs (cast iron head) | 22 | 30 |
Oil pump bolt | 65 | 88 |
Timing chain cover bolts80 in-lb | 6.7 | 9 |
Distributor hold-down bolt | 25 | 34 |
Rocker arm nut (hydraulic flat-tappet) Zero lash + ½ additional turn. | 20 | 27 |
Always verify with an OEM service manual.
Specs here are general references. Values vary by engine year, bolt grade, lubricant, and machining. For critical fasteners (head bolts, main caps, rod bolts) always use the correct torque sequence and the proper lubricant (engine oil, assembly lube, or ARP lube depending on the fastener). Engine block or head machining can require updated specs.
About TTY (Torque-to-Yield) Bolts
Torque-to-yield bolts are designed to stretch slightly past their yield point during installation — creating a more consistent clamp load. Because they've permanently deformed, they must be replaced every time they are removed. Reusing TTY bolts risks under-clamping, head gasket failure, or bolt breakage. Always buy new bolts for engine reassembly when TTY is specified (common on LS engines, modern imports, and many late-model V8s).
General Fastener Notes
General fastener values are dry torque — no oil or lubricant. If threads are lubricated, reduce torque by approximately 15–20%. Grade is marked on the bolt head: SAE Grade 5 = 3 radial lines, Grade 8 = 6 radial lines. Metric class is stamped directly (8.8, 10.9, 12.9). Never torque a fastener based on grade alone without checking application-specific requirements.