The ARP Header Bolt Kit provides high-strength replacement hardware for mounting compatible exhaust headers on Chevrolet Gen III and Gen IV LS-series engines. It includes twelve M8 × 1.25 bolts measuring 0.984 inch under the head, along with premium-quality washers.
This version is designed for headers using approximately 1/4-inch-thick mounting flanges. Its shorter 0.984-inch bolt length helps provide appropriate thread engagement when used with a compatible header flange, gasket, and LS cylinder head.
Features
- Header bolt kit for Chevrolet Gen III and Gen IV LS-series engines
- Designed for headers with approximately 1/4-inch-thick mounting flanges
- Manufactured from ARP 8740 chrome-moly steel
- Black oxide finish
- Compact 12-point heads help improve tool access around exhaust tubes
- M8 × 1.25 threads
- 0.984-inch under-head length
- Includes twelve bolts and matching washers
- ARP part number 134-1201
Fitment
- Chevrolet LS-series Gen III engines
- Chevrolet LS-series Gen IV engines
Designed for compatible LS cylinder heads and exhaust headers using M8 × 1.25 mounting threads and approximately 1/4-inch-thick header flanges.
Important: The 1/4-inch measurement describes the intended header-flange thickness. These are metric M8 × 1.25 bolts and do not have 1/4-inch threads.
Fitment depends on the combined thickness of the header flange and gasket, the depth of the threaded cylinder-head holes, and the required amount of thread engagement. Compare the specifications below with the header manufacturer’s requirements before ordering.
Specifications
- Manufacturer: ARP
- Part number: 134-1201
- 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
- Thread size: M8 × 1.25
- Under-head length: 0.984 inch (approximately 25 mm)
- Intended header-flange thickness: Approximately 1/4 inch
- Bolt quantity: 12
- Washers included: Yes
Choosing Between ARP 134-1201 and 134-1202
- ARP 134-1201: 0.984-inch under-head length for approximately 1/4-inch header flanges
- ARP 134-1202: 1.181-inch under-head length for approx
Proposition 65 Warnings.
Cancer and Reproductive Harm. See details below.
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