Mopar LA Small Block V8

Intro

The LA small block is familiar enough to make Mopar people careless.

That is the trap. The 273, 318, 340, and 360 belong to the same LA family, but head-bolt values, rocker-shaft torque, intake hardware, 360 balance parts, replacement fasteners, and later mixed builds can still bite. “Small-block Mopar” is a starting point, not a license to stop reading.

General Torque Specs

Bottom End		Top End
Main Cap Bolts	85 lb-ft	Cylinder Head Bolts	85 lb-ft1 95 lb-ft2
Connecting Rod Nuts	45 lb-ft	Rocker Shaft Bolts	17 lb-ft3
Oil Pump Attaching Bolt	35 lb-ft	Spark Plugs	30 lb-ft
Oil Pump Cover Bolt	95 in-lb	Valve Cover Bolts	7 lb-ft4
Oil Pan Bolts	15 lb-ft
Intake and Exhaust		Driveline Side
Intake Manifold Bolts	35 lb-ft5	Flywheel / Flexplate Bolts	55 lb-ft
Exhaust Manifold Bolts / Nuts	30 lb-ft	Torque Converter Bolts	270 in-lb
Carburetor Mounting Nuts	7 lb-ft4	Bellhousing / Flywheel Housing Bolts	50 lb-ft
		Starter Mounting Bolts	50 lb-ft
External Engine
Harmonic Damper Bolt	135 lb-ft	Water Pump Bolts	30 lb-ft
Camshaft Lock Bolt	35 lb-ft	Fuel Pump Bolts	30 lb-ft
Timing Cover Bolts, Cast Cover	30 lb-ft	Distributor Hold-Down Bolt	15 lb-ft

¹ 273 / 318 cylinder-head bolt value.

² 340 / 360 cylinder-head bolt value.

³ Factory-style LA rocker-shaft bolts are 17 lb-ft. Do not use the common wrong 30 lb-ft chart value unless the actual aftermarket parts call for it.

⁴ Thin covers, carburetor flanges, and cork-style gaskets distort easily. Tighten evenly and do not turn seep control into bent metal.

⁵ Cast-iron-head factory-style intake value. Aluminum heads, aftermarket intakes, and special gaskets use their own instructions.

Aftermarket bolts, studs, rods, aluminum heads, intake manifolds, roller rockers, replacement fasteners, and modified LA 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 25-30, don’t give one exhaust bolt 25, the next one 28, 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

• Head-bolt value changes by engine. A 273 / 318 value and a 340 / 360 value are not interchangeable just because the heads look like they came from the same neighborhood.
• The rocker-shaft row is where bad internet charts earn their reputation. LA rocker-shaft bolts are low-torque hardware. Hit them with 30 lb-ft and you may learn about stripped threads, crushed shafts, or broken bolts.
• The 360 uses external-balance parts. That does not change head-bolt torque, but it absolutely matters when flywheels, flexplates, dampers, and converter weights enter the conversation.
• Factory-style intake torque assumes the matching factory-style parts. Aluminum heads, aftermarket intakes, thin gaskets, or odd mixed builds follow the part maker’s instructions.
• Valve covers, oil pans, and carburetor flanges are easy to distort. If the gasket squeezes out, that was not extra sealing. That was you.

Common Mistakes

• Using the 273 / 318 head-bolt number on a 340 / 360 because all LA engines looked close enough.
• Torquing LA rocker-shaft bolts to 30 lb-ft because some chart on the internet said so.
• Forgetting 360 external-balance parts and chasing a vibration like the torque wrench caused it.
• Using aftermarket intake, head, rod, or rocker hardware with factory torque numbers after the parts came with their own instructions.
• Cranking valve-cover, oil-pan, or carburetor hardware down like the gasket owes you rent.
• Reading a range and scattering random values across head bolts, intake bolts, or matched driveline fasteners like that was ever a plan.

Bottom Line

The LA small block is common, useful, and easy to underestimate.

That is exactly how people get sloppy.

Use the right head-bolt value, respect the rocker-shaft torque, match the 360 balance parts, keep matched fasteners consistent, and don’t let “small-block Mopar” do your thinking.