Mopar Gen II Hemi V8

Intro

The Gen II Hemi is the 426 Hemi. That does not mean every “Hemi” number belongs here.

This engine has its own rules. It is not a Gen I early Hemi, not a wedge, not a modern Gen III Hemi, and not a place to use folklore because the valve covers made everybody lose their mind. The 426 Hemi uses different bottom-end clamping, cross-bolted main hardware, specific rod hardware, different head-bolt values by head material, and intake hardware that will punish people who think all big-block Mopar numbers are close enough.

General Torque Specs

Bottom End		Top End
Main Cap Bolts	100 lb-ft	Cylinder Head Bolts, Iron Heads	70-75 lb-ft1
Main Cap Tie Bolts	45 lb-ft	Cylinder Head Bolts, Aluminum Heads	65-70 lb-ft1
Connecting Rod Bolts, 7/16 in.	75 lb-ft	Rocker Shaft Bracket Bolts	30 lb-ft max2
Oil Pump Attaching Bolt	35 lb-ft	Spark Plugs	30 lb-ft
Oil Pump Cover Bolt	10 lb-ft	Valve Cover Bolts	6-7 lb-ft3
Oil Pan Bolts	15 lb-ft
Intake and Exhaust		Driveline Side
Intake Manifold Bolts	8 lb-ft4	Flywheel / Flexplate Bolts	55 lb-ft
Exhaust Manifold Bolts	30 lb-ft	Torque Converter Bolts	270 in-lb
Carburetor Mounting Nuts	7 lb-ft3	Bellhousing / Flywheel Housing Bolts	50 lb-ft
		Starter Mounting Bolts	50 lb-ft
External Engine
Harmonic Damper Bolt	135 lb-ft	Camshaft Cap Screw, Street Hemi	40 lb-ft5
Camshaft Cap Screw, Race Hemi	75 lb-ft5	Water Pump Bolts	30 lb-ft
Fuel Pump Bolts	30 lb-ft	Timing Cover Bolts	10 lb-ft
Distributor Hold-Down Bolt	15 lb-ft

¹ Head-bolt value changes by head material. Iron and aluminum heads are not the same row wearing different paint.

² Rocker shaft bracket bolts are listed as a maximum value. Aftermarket rocker gear, stands, shafts, and fasteners follow the part maker.

³ Thin covers, carburetor flanges, and cork-style gaskets distort easily. Tighten evenly and do not turn seep control into bent metal.

⁴ 426 Hemi intake hardware is low-torque hardware. Do not drag wedge intake numbers into this row unless cracking expensive parts sounds fun.

⁵ Street Hemi and race Hemi camshaft cap screws do not use the same value. Match the actual parts.

Aftermarket bolts, studs, rods, aluminum heads, intake manifolds, rocker hardware, replacement fasteners, race parts, and modified 426 Hemi hardware use the part maker’s number and lube instructions. Don’t use this chart to overrule the parts in your hand.

A range is not a game of horseshoes. If a matched set shows 70-75, don’t give one head bolt 70, the next one 73, and the last one whatever your elbow liked. Pick one value in the range and use it consistently across the set unless the real procedure says certain fasteners get different numbers.

Notes

• The 426 Hemi has cross-bolted main hardware. Main cap bolts and main cap tie bolts are separate rows because they are not doing the same job with the same value.
• Head material matters. Iron-head and aluminum-head bolt values are different, and pretending aluminum is just shiny iron is how expensive lessons get scheduled.
• The intake manifold row is a trap. The 426 Hemi intake value is far lower than normal wedge intake numbers. If you torque it like a wedge, the engine may not forgive your confidence.
• Street Hemi and race Hemi camshaft cap screws use different values. Do not pick the bigger number because race parts sounded cooler.
• Rocker shaft bracket bolts have a listed maximum. Aftermarket rocker gear follows the part maker, not bench-racing memory.

Common Mistakes

• Using Gen I Hemi or wedge torque numbers on a 426 Hemi because the badge said Hemi or the block said Mopar.
• Forgetting the main cap tie bolts and treating the bottom end like a normal two-bolt or four-bolt setup.
• Using the iron-head value on aluminum heads, or the aluminum-head value on iron heads, because checking the head material apparently felt optional.
• Torquing the 426 Hemi intake like a wedge intake and then acting surprised when expensive parts complain.
• Using the race Hemi camshaft cap screw value on a street Hemi, or the street value on race hardware.
• Using aftermarket head, intake, rod, rocker, or race hardware with factory torque numbers after the parts came with their own instructions.

Bottom Line

The Gen II Hemi is the 426 Hemi, and it earned the reputation.

It also earned its own torque chart.

Use the 426-specific numbers, separate the main cap bolts from the tie bolts, match the head material, respect the low intake torque, check street versus race hardware, and don’t let the word “Hemi” do your thinking.