Product Description:
These polished stainless steel header bolts are specified for compatible LS headers with a 3/8-inch flange. The set supplies 12 hex-head bolts with a 30 mm (1.181-inch) underhead length and M8 x 1.25 threads.
| Producer | ARP |
|---|---|
| Product type | Hex-head header bolt kit |
| Application | GM LS Gen III / Gen IV headers with 3/8-inch-thick flanges and M8 x 1.25 threads |
| Material | Stainless steel |
| Finish | Polished |
| Condition | New performance part |
| Quantity | 12 header bolts with washers |
| Engine / assembly | Required configuration |
|---|---|
| GM LS Gen III | Compatible headers with 3/8-inch flange; M8 x 1.25 cylinder-head threads |
| GM LS Gen IV | Same flange, thread and engagement checks required |
Select by the installed engine and component configuration. Vehicle year alone does not establish compatibility, particularly after an engine swap.
- 12 polished stainless steel hex-head header bolts
- Companion washers
Flange thickness matters when selecting header bolts. Match the flange, gasket and available threaded depth so the bolts clamp the header correctly without bottoming in the cylinder head. The hex heads provide a different wrenching arrangement from the corresponding 12-point kit.
| Thread | M8 x 1.25 |
|---|---|
| Underhead length | 30 mm / 1.181 inches |
| Header flange | 3/8 inch |
| Quantity | 12 bolts |
| Head style | Hex |
- Measure header flange thickness and compare the required underhead length.
- Check thread engagement, available hole depth and wrench clearance around the header tubes.
- Follow current kit and header-manufacturer instructions for lubricant, tightening sequence and torque.
What flange thickness is this kit intended for?
A 3/8-inch-thick header flange on a compatible LS application.
What is the bolt length?
The underhead length is 30 mm, or 1.181 inches.
What threads do these bolts use?
M8 x 1.25.
How many header bolts are supplied?
The kit contains 12 bolts with companion washers.
Can I substitute these for a shorter header bolt?
Check flange thickness and usable thread depth first. A longer bolt can bottom before it clamps the flange.
If outside the lower 48 states please email us for a shipping quote: Orders@Hawksmotorsports.com
