The ARP Header Bolt Kit provides high-strength replacement hardware for installing compatible exhaust headers on Chevrolet Gen III and Gen IV LS-series engines. It includes twelve M8 header bolts measuring 1.181 inches under the head, along with matching washers.
These bolts are sized for headers using approximately 3/8-inch-thick mounting flanges. They feature compact 12-point heads that accept a 10 mm 12-point socket, providing improved tool access in confined areas around the cylinder heads and exhaust tubes.
Features
- Header bolt kit for Chevrolet Gen III and Gen IV LS-series engines
- Designed for headers with approximately 3/8-inch-thick mounting flanges
- Manufactured from ARP 8740 chrome-moly steel
- Black oxide finish
- Compact 12-point bolt heads help improve tool access
- 10 mm 12-point socket size
- Rolled-thread construction
- Includes twelve bolts and matching washers
- ARP part number 134-1202
Fitment
- Chevrolet LS-series Gen III engines
- Chevrolet LS-series Gen IV engines
Designed for compatible LS cylinder heads and exhaust headers using M8 mounting threads and approximately 3/8-inch-thick header flanges.
Important: The 3/8-inch measurement describes the intended header-flange thickness. These are M8 bolts and do not have 3/8-inch threads.
Header flange thickness, gasket thickness, mounting-hole depth, and required thread engagement can differ between exhaust systems. Compare the dimensions below with the cylinder head and header manufacturer’s requirements before ordering.
Specifications
- Manufacturer: ARP
- Part number: 134-1202
- Application: Chevrolet LS Gen III and Gen IV
- Fastener type: Exhaust header bolt
- Material: 8740 chrome-moly steel
- Finish: Black oxide
- Head style: 12-point
- Socket size: 10 mm 12-point
- Thread size: M8
- Under-head length: 1.181 inches (approximately 30 mm)
- Intended header-flange thickness: Approximately 3/8 inch
- Bolt quantity: 12
- Washers included: Yes
Recommended Use
Recommended when installing compatible aftermarket headers, replacing worn or damaged header hardware, or assembling a Chevrolet Gen III or Gen IV LS engine that requires M8 header bolts for a 3/8-inch-thick flange.
These bolts should not be selected solely because the engine belongs to the LS family. Confirm the required bolt diameter, usable length, flange thickness, gasket thickness, and threaded-hole depth for the specific cylinder-head and header combination.
What’s Included
- 12 ARP M8 12-point header bolts
- Matching washers
- ARP part number 134-1202
Exhaust headers, header gaskets, socket, thread lubricant, and other installation components are not included unless otherwise specified.
Installation
Before installation, compare the new bolts with the header flange, gasket, and threaded cylinder-head holes. Make sure the bolts provide sufficient thread engagement without bottoming in the holes.
Clean the cylinder-head threads and inspect the header flanges and gaskets before assembly. Start every bolt by hand to prevent cross-threading. Tighten the fasteners gradually using the sequence and torque procedure recommended by the header or engine manufacturer.
Torque requirements depend on the cylinder-head material, gasket design, thread condition, and lubricant or thread-locking compound used. Do not apply a generic torque value without confirming the correct installation procedure for the specific setup.
After the engine has completed the recommended heat-cycle procedure, inspect the installation and recheck the fasteners if instructed by the header manufacturer.
Proposition 65 Warnings.
Cancer and Reproductive Harm. See details below.
Items that are not CARB Legal will not be sold and ship to California or CARB states.
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