Pro Series GM Gen III/IV LS Header Bolt Kit
Pro Series GM Gen III/IV LS Header Bolt Kit
SKU: SKU: 734-86052
In stock
Product Details
Features
- 35 chromoly bolts resist stretching and loosening vs. reused factory hardware
- Hex head bolts fit standard header/exhaust manifold flange installation
- Fits GM Gen III/IV LS engines: 4.8L, 5.3L, 5.7L, 6.0L, 6.2L
- 28 ft-lb torque spec for consistent, reliable header flange sealing
Description
Secure your exhaust system with this Pro Series header bolt kit, designed for GM Gen III and Gen IV LS engines. Factory bolts can loosen over time due to heat cycles and vibration, leading to exhaust leaks and reduced performance — this kit provides reliable clamping force and consistent fitment to help maintain a tight seal between the cylinder head and exhaust manifold or header flange.
Manufactured from 35 chromoly steel, these hex head bolts resist stretching and loosening compared to worn or reused factory hardware, and are built to handle the high-temperature environments common in LS engine applications. Whether you're installing aftermarket headers or refreshing factory-style hardware, this kit delivers dependable clamping performance.
Installation torque spec is 28 ft-lbs.
Applications
Fits Chevrolet Small Block V8 Gen III/IV (LS-Based): 4.8L/293 in³ (LR4/LY2), 5.3L/325 in³ (LM7/L59/LC9/LH6/LY5), 5.7L/346 in³ (LS1/LS6), 6.0L/364 in³ (LQ4/LQ9/LS2), 6.2L/376 in³ (LS3/L92/L99). Common on Silverado/Sierra, Camaro/GTO, Corvette (C5/C6), Cadillac CTS-V, and GM LS engine swap applications.
Installation
Torque to 28 ft-lbs. Designed for header/exhaust manifold flange installation.
Hardware Details
35 chromoly steel, black finish, hex head style. M8 x 1.25 thread, approximately 25mm underhead length. Sold as a complete kit.
Specs
| Torque | 28ft-lbs |
| Color | Black |
| Fastener Type | Header / exhaust manifold bolt |
| Grade | Performance |
| Head Style | Hex |
| Material | 35 Chromoly Steel |
| Thread Size | M8 x 1.25 |
| Length | Approx. 25mm underhead |
| Quantity | Sold as a kit |
Engine Fitment
COMPATIBLE WITH
Chevrolet Small Block V8 Gen. III/IV (LS-Based)
• 4.8L / 293 in3 (LR4 / LY2)
• 5.3L / 325 in3 (LM7 / L59 / LC9 / LH6 / LY5)
• 5.7L / 346 in3 (LS1 / LS6)
• 6.0L / 364 in3 (LQ4 / LQ9 / LS2)
• 6.2L / 376 in3 (LS3 / L92 / L99)
NOTES
• M8 x 1.25 thread, ~25mm underhead length, hex head, 35 chromoly steel.
• Torque spec: 28 ft-lbs.
• Designed for header/exhaust manifold flange installation.
COMMON VEHICLE APPLICATIONS
Chevrolet Silverado / GMC Sierra (4.8L / 5.3L / 6.0L / 6.2L)
Chevrolet Camaro / Pontiac GTO (LS1 / LS2 / LS3)
Chevrolet Corvette (C5 / C6 LS engines)
Cadillac CTS-V (LS-based engines)
GM LS engine swap applications
Q&A
Will this fit a 5.3L Silverado or Sierra?
Yes. The 5.3L is covered under this kit's GM Gen III/IV LS-based engine fitment, including common LM7, L59, LC9, LH6, and LY5 applications.
Does this kit work on an LS1 Camaro?
Yes. This kit fits 5.7L LS1/LS6 applications, including compatible Camaro and Firebird models.
What torque spec should I use for installation?
28 ft-lbs.
Will this fit a Corvette C5 or C6 with an LS engine?
Yes, for compatible Gen III/IV LS-powered C5 and C6 Corvette applications.
What thread size are these bolts?
M8 x 1.25, with an approximate 25mm underhead length.
Can I use this kit with aftermarket headers?
Yes. This kit can be used for aftermarket header or factory-style exhaust manifold installation, provided the flange thickness and required bolt length are compatible.
What material are these bolts made from?
35 chromoly steel with a black finish and hex-head design.
Emissions Notice
This product does not affect vehicle emissions and is not subject to emissions compliance regulations.
Pro Series GM Gen III/IV LS Header Bolt Kit
Secure your exhaust system with this Pro Series header bolt kit, designed for GM Gen III and Gen IV LS engines. Factory bolts can loosen over time due to heat cycles and vibration, leading to exhaust leaks and reduced performance — this kit provides reliable clamping force and consistent fitment to help maintain a tight seal between the cylinder head and exhaust manifold or header flange.
Manufactured from 35 chromoly steel, these hex head bolts resist stretching and loosening compared to worn or reused factory hardware, and are built to handle the high-temperature environments common in LS engine applications. Whether you're installing aftermarket headers or refreshing factory-style hardware, this kit delivers dependable clamping performance.
Installation torque spec is 28 ft-lbs.
Applications
Fits Chevrolet Small Block V8 Gen III/IV (LS-Based): 4.8L/293 in³ (LR4/LY2), 5.3L/325 in³ (LM7/L59/LC9/LH6/LY5), 5.7L/346 in³ (LS1/LS6), 6.0L/364 in³ (LQ4/LQ9/LS2), 6.2L/376 in³ (LS3/L92/L99). Common on Silverado/Sierra, Camaro/GTO, Corvette (C5/C6), Cadillac CTS-V, and GM LS engine swap applications.
Installation
Torque to 28 ft-lbs. Designed for header/exhaust manifold flange installation.
Hardware Details
35 chromoly steel, black finish, hex head style. M8 x 1.25 thread, approximately 25mm underhead length. Sold as a complete kit.
COMPATIBLE WITH
Chevrolet Small Block V8 Gen. III/IV (LS-Based)
• 4.8L / 293 in3 (LR4 / LY2)
• 5.3L / 325 in3 (LM7 / L59 / LC9 / LH6 / LY5)
• 5.7L / 346 in3 (LS1 / LS6)
• 6.0L / 364 in3 (LQ4 / LQ9 / LS2)
• 6.2L / 376 in3 (LS3 / L92 / L99)
NOTES
• M8 x 1.25 thread, ~25mm underhead length, hex head, 35 chromoly steel.
• Torque spec: 28 ft-lbs.
• Designed for header/exhaust manifold flange installation.
COMMON VEHICLE APPLICATIONS
Chevrolet Silverado / GMC Sierra (4.8L / 5.3L / 6.0L / 6.2L)
Chevrolet Camaro / Pontiac GTO (LS1 / LS2 / LS3)
Chevrolet Corvette (C5 / C6 LS engines)
Cadillac CTS-V (LS-based engines)
GM LS engine swap applications
SPECIFICATIONS
Torque: 28ft-lbs
Color: Black
Fastener Type: Header / exhaust manifold bolt
Grade: Performance
Head Style: Hex
Material: 35 Chromoly Steel
Thread Size: M8 x 1.25
Length: Approx. 25mm underhead
Quantity: Sold as a kit
