ARP LS Header Bolt Kit for Chevrolet Gen III/LS — 3/8" Chromoly Bolts, 170,000 psi

ARP 134-1202 is a high-strength chromoly header bolt kit engineered to secure Chevrolet Gen III/LS headers with durable 3/8" wide fasteners rated at 170,000 psi.

When installing or replacing headers on Gen III/LS Chevrolet engines, using bolts designed for the task ensures a reliable seal and long service life. ARP builds these kits from chromoly steel heat-treated for exceptional tensile strength, so they resist stretching and fatigue under repeated thermal cycling. Each kit contains the exact quantity of components required for the application, plus high-quality washers and the choice of hex or 12-point heads, finished in black oxide for corrosion resistance and a clean appearance.

Why choose ARP chromoly fasteners for my LS header installation?

ARP's chromoly bolts offer much higher load capacity than many OE or generic alternatives, reducing the risk of failure from vibration, heat, or overtightening. Their tensile rating and heat treatment process deliver consistent clamp force across multiple uses and rebuilds.

• 170,000 psi tensile strength for superior durability
• Chromoly construction resists stretching and fatigue
• Black oxide finish adds corrosion protection and low-glare appearance
• Kits include premium washers to protect flange surfaces

How complete is this ARP kit for Chevrolet Gen III/LS headers?

The kit is assembled specifically for Gen III/LS header patterns and supplies the correct number of fasteners and accessories for a proper install. You get parts matched to the application so no last-minute trips to the parts store.

• Contains the exact quantity of bolts required for the specified application
• Includes premium washers to ensure even load distribution
• Available in hex or 12-point head styles to suit your tooling preference
• Packaged for immediate use during header installation or replacement

Will these bolts hold up to repeated heat cycles and track use?

The combination of chromoly alloy and ARP's heat-treatment yields bolts that maintain clamp integrity through aggressive thermal cycling. That stability is important for exhaust flanges that see wide temperature swings and vibration during spirited driving or racing.

• Heat-treated chromoly resists permanent deformation under load
• High tensile strength minimizes the chance of bolt failure
• Washers help preserve flange flatness and gasket sealing over time

What torque or installation notes should I follow for best results?

Follow ARP's recommended torque sequence and values for header bolts, and use a calibrated torque wrench for accurate clamp load. Lubrication or ARP-specified assembly products may be advised to achieve consistent torque readings and prevent galling.

• Use proper torque wrench and follow a cross-pattern tightening sequence
• Refer to ARP documentation for lubrication and torque values
• Choose hex or 12-point heads based on available space and tools

Who is this for? The ARP 134-1202 Chromoly Header Bolt Kit is intended for enthusiasts and professional mechanics working on Chevrolet Gen III/LS engines who want a dependable, long-lasting fastener solution. It’s ideal for anyone replacing factory bolts, upgrading for higher durability under performance use, or rebuilding an engine where consistent flange clamping and corrosion-resistant finish are priorities.