Head Bolts

Head Bolts: the fasteners that hold your clamp load when the cylinders push back

Head bolts do one job and do it under pressure: they clamp the cylinder head to the block hard enough that the head gasket seals against combustion, coolant, and oil while the engine tries to blow it all apart. When you torque a fresh set of head bolts to spec, you are setting the clamp load that keeps the gasket squeezed through every firing event. People replace them when they pull a head, upgrade a gasket, or build for more power than the factory hardware was picked for, because a stretched or reused bolt does not hold the load it used to.

What ThreePiece stocks in head bolt kits

We have 16 head bolt kits in stock right now, priced from $117 to $291. That is the current range for what is on the shelf, not a promise on any one kit. Two brands cover the range: ARP makes up most of it with 14 kits, and S&S Cycle covers the other two. So this category splits cleanly into automotive engine hardware and V-twin motorcycle hardware.

On the automotive side, the ARP Chevy Gen III/LS9 Small Block Head Bolt Kit sits at the top of the range at $291.16, and the ARP LT1 6.2L kit with M8 corner bolts covers the later small block at $277.27. On the V-twin side, the S&S Cycle 86-03 XL Head Bolt Kit is $169.76, and the S&S Cycle 7/16-20 x 2-3/8in TD Head Bolt Kit 10-Pack runs $133.76.

Fitment is listed on 3 of these kits, spanning model years 1986 to 2023, with makes including Chevrolet, Toyota, Harley-Davidson, Audi, and Volkswagen. Named vehicles include the Toyota Supra, Harley-Davidson Sportster, and various Chevrolet applications. Confirm your exact application before buying.

How to choose the right kit

The first cut is the platform: pick the kit built for your engine. An LS-family small block, an LT1, and a Sportster all use different bolt patterns, thread sizes, and lengths, so the kit is chosen by the engine, not by preference. The second consideration is the bolt count and pack format. Kits like the S&S 10-Pack are supplied for a specific torque-down layout, so match the pack to the number of fasteners your head actually uses. Higher-priced kits here generally cover larger or later-model engines, not a better grade of the same part.

What else you need with it

Head bolts go in with a new gasket, so plan on Head Gaskets or a full Gasket Kit when you have the head off. If you are that deep, it is a good time to check Bearings and Pistons. Browse the rest of Engine Components for the supporting parts. Related fastening and plumbing lives in Fittings and Adapters.

Fitment help and ordering

Not sure a kit matches your engine? Call our fitment line at 813-535-5801 or reach us through contact us. Every order ships free, and Affirm and Katapult financing is available at checkout.

Head Bolts: the fasteners that hold your clamp load when the cylinders push back

Head bolts do one job and do it under pressure: they clamp the cylinder head to the block hard enough that the head gasket seals against combustion, coolant, and oil while the engine tries to blow it all apart. When you torque a fresh set of head bolts to spec, you are setting the clamp load that keeps the gasket squeezed through every firing event. People replace them when they pull a head, upgrade a gasket, or build for more power than the factory hardware was picked for, because a stretched or reused bolt does not hold the load it used to.

What ThreePiece stocks in head bolt kits

We have 16 head bolt kits in stock right now, priced from $117 to $291. That is the current range for what is on the shelf, not a promise on any one kit. Two brands cover the range: ARP makes up most of it with 14 kits, and S&S Cycle covers the other two. So this category splits cleanly into automotive engine hardware and V-twin motorcycle hardware.

On the automotive side, the ARP Chevy Gen III/LS9 Small Block Head Bolt Kit sits at the top of the range at $291.16, and the ARP LT1 6.2L kit with M8 corner bolts covers the later small block at $277.27. On the V-twin side, the S&S Cycle 86-03 XL Head Bolt Kit is $169.76, and the S&S Cycle 7/16-20 x 2-3/8in TD Head Bolt Kit 10-Pack runs $133.76.

Fitment is listed on 3 of these kits, spanning model years 1986 to 2023, with makes including Chevrolet, Toyota, Harley-Davidson, Audi, and Volkswagen. Named vehicles include the Toyota Supra, Harley-Davidson Sportster, and various Chevrolet applications. Confirm your exact application before buying.

How to choose the right kit

The first cut is the platform: pick the kit built for your engine. An LS-family small block, an LT1, and a Sportster all use different bolt patterns, thread sizes, and lengths, so the kit is chosen by the engine, not by preference. The second consideration is the bolt count and pack format. Kits like the S&S 10-Pack are supplied for a specific torque-down layout, so match the pack to the number of fasteners your head actually uses. Higher-priced kits here generally cover larger or later-model engines, not a better grade of the same part.

What else you need with it

Head bolts go in with a new gasket, so plan on Head Gaskets or a full Gasket Kit when you have the head off. If you are that deep, it is a good time to check Bearings and Pistons. Browse the rest of Engine Components for the supporting parts. Related fastening and plumbing lives in Fittings and Adapters.

Fitment help and ordering

Not sure a kit matches your engine? Call our fitment line at 813-535-5801 or reach us through contact us. Every order ships free, and Affirm and Katapult financing is available at checkout.