1968-1970 Charger 440 RB Head Bolt Torque (Plus 426 Hemi Notes)

440 RB head bolt torque

For the 440 cubic-inch RB (raised-block) big-block in 1968-1970 Dodge Charger R/T cars with iron heads and factory bolts:

• Final head bolt torque: 70 ft-lb
• Sequence: start at center, work outward in three passes
• Pass values: 35 → 55 → 70 ft-lb
• Lubricant: engine oil on threads (not anti-seize)

This is the value for factory iron heads and factory bolts. Aftermarket aluminum heads, ARP studs, and stroker builds will have different specs from the head/hardware manufacturer that you should follow instead.

Why Mopar B/RB torque differs from GM and Ford big-blocks

The Mopar B-engine and RB-engine families (which include the 350, 361, 383, 400, and 440) share architecture across the entire B/RB line. Head bolt torque is 70 ft-lb across the family — the 383 and the 440 use the same value because they share the same head bolt geometry.

This is different from:

• GM big-block (BBC, 396/427/454): 80 ft-lb on long bolts, more aggressive than Mopar
• Ford FE big-block (390/427/428): 80-90 ft-lb depending on year and procedure

If you're a builder coming from the GM or Ford world, the Mopar value will feel low. It is. Mopar B/RB engines were over-engineered in head clamping load and don't need the higher torques that GM and Ford big-blocks use.

426 Hemi is completely different

The 426 Hemi is an entirely different engine from the 440 RB despite both being available in the same model years. The Hemi has hemispherical combustion chambers, a completely different head architecture, and its own torque specifications:

• 426 Hemi head bolt torque: unique values that you must verify against the Hemi-specific shop manual
• The Hemi has main cap bolts, head bolts, and rod bolts that all differ from the 440 RB

Do not apply 440 RB specs to a 426 Hemi build. If you're working on a documented Hemi car, get the Hemi shop manual (Chrysler issued a 426-specific addendum in addition to the standard B-engine literature) and follow those specs to the letter. Hemi parts are expensive, scarce, and unforgiving of build errors.

383 B-engine cars

If you have a 1968-1970 Charger with the 383 B-engine (more common than the 440 RB in lower-trim cars), the head bolt torque is the same as the 440: 70 ft-lb final. The 383 and 440 share head architecture — different bore and stroke, same head deck dimensions, same head bolt geometry, same torque spec.

Main cap and rod bolt torque (440 RB)

For completeness on a 440 RB rebuild, the bottom-end specs:

• Main cap bolts: 85 ft-lb final, three passes (35 → 60 → 85)
• Rod bolts: 50 ft-lb final, two passes (25 → 50)
• Intake manifold bolts: 40 ft-lb final
• Spark plugs: 30 ft-lb final
• Harmonic balancer bolt: 135 ft-lb final (this is one of the highest values on the engine — Mopar uses a substantial fastener for the front of the crank)
• Flywheel bolts: 55 ft-lb final

Verify all of these against the Chrysler shop manual for your specific year — there were minor variations across the 1968-1970 run.

When to deviate

Use the head/hardware manufacturer's spec instead if you're running:

• ARP studs (B/RB): typically 65-70 ft-lb with ARP molybdenum lubricant — verify the ARP instructions for your specific stud kit
• Aftermarket aluminum heads: Edelbrock Performer RPM, Indy, Stage V, or other aluminum head options have manufacturer-specific torque specs that you should follow
• Aluminum heads on iron block: head gasket selection changes; check the gasket manufacturer's spec
• 440 stroker builds (505+): if the bottom-end has been substantially rebuilt with aftermarket forgings or studs, use the build documentation specs — not the factory spec

Common mistakes

1. Applying GM big-block specs to a 440 RB. The 440 needs 70 ft-lb final; the GM 454 needs 80 ft-lb. Over-torquing a Mopar 440 stretches the bolts and damages the threads in the block.
2. Applying 440 specs to a 426 Hemi. Different engine, different heads, different specs.
3. Skipping the three-pass sequence. Three passes apply gradually increasing clamp load and avoid distorting the head.
4. Anti-seize on threads. Reduces friction and over-torques the bolt by 20-30%.
5. Reusing damaged or stretched bolts. Inspect each bolt — if any show stretch (visible thread waist), corrosion, or damage, replace the entire set.

A reminder on safety

These are research-derived starting values, not factory shop manual data for your specific engine. Always verify against the actual factory service manual for your specific year and engine — head bolt torque on a Mopar B/RB engine is a high-stakes spec, and Hemi engines especially are unforgiving of build errors. The Mopar B/RB family is robust when built correctly, finicky when built wrong.