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Precision Cut Single Bank Stainless Header Flange for GM LS1 Custom Exhaust Fabrication
The 7046-AS is a single bank 1 7/8 inch stainless header flange for GM LS1 engines, providing the precision machined flange plate that fabricators need to build custom headers or replace a damaged flange on an existing set. Header flanges are the foundation of any header design, and the dimensional accuracy of the flange determines whether the header will seal correctly against the cylinder head, mount without binding, and maintain a flat mating surface through repeated heat cycles. Kooks machines this flange to the same specifications used in their production LS1 header builds, giving custom fabricators access to a flange that matches factory Kooks dimensional standards.
The 1 7/8 inch port opening of the 7046-AS matches the primary tube size for standard LS1 header primary tube diameters, and the single bank format covers one cylinder head, meaning a complete V8 header set requires two flanges. Whether you are building a custom one off header, repairing cracked flanges on an existing set, or fabricating a budget header using quality Kooks components as the foundation, this flange is the correct starting point for a GM LS1 application. Stainless material ensures the flange holds its shape and surface flatness through years of heat cycling without the warping that plagues mild steel alternatives.
Key Features
- Single bank flange for one cylinder head of a GM LS1 V8 engine
- 1 7/8 inch port opening for standard LS1 primary tube diameter
- Precision machined to Kooks production header specifications
- Stainless steel construction for flatness retention under heat cycling
- Correct bolt hole pattern for GM LS1 cylinder head exhaust ports
- Suitable for custom header fabrication and flange replacement
What's Included
- 1 x this flange single bank 1 7/8 inch LS1 header flange
Specifications
| Specification | Detail |
|---|---|
| Part Number (MPN) | 7046-AS |
| UPC | Contact us for UPC |
| Port Opening | 1 7/8 inch |
| Coverage | Single Bank (One Cylinder Head) |
| Application | GM LS1 Engines |
| Material | Stainless Steel |
| Use | Custom Header Fabrication and Flange Replacement |
Frequently Asked Questions
What engine does this flange fit?
This flange is designed for GM LS1 engines. It uses the correct bolt hole pattern and port opening dimensions for the LS1 cylinder head exhaust port configuration.
Does this flange cover both cylinder heads?
No. This flange is a single bank flange that covers one cylinder head. A complete V8 header build requires two flanges, one per bank.
What primary tube diameter does this flange accept?
This flange has a 1 7/8 inch port opening, which is designed to accept 1 7/8 inch primary header tubes for welding.
Is this flange compatible with other LS engine variants besides the LS1?
This flange is specified for LS1 applications. Other LS variants such as LS2, LS3, and LS7 may use different head castings with different port dimensions. Verify compatibility with your specific head casting before ordering.
What is the material of this flange?
Stainless steel, providing dimensional stability and resistance to warping under the high temperatures of a performance exhaust system.
Can I use this flange with Kooks production header tubes?
Yes. This flange is designed to accept Kooks production primary tube sizing and bolt patterns, making it compatible with Kooks header fabrication components.
How is the primary tube attached to this flange flange?
The primary header tube is inserted into the port opening of this flange and welded in place using TIG welding with an appropriate stainless filler material.
Does this flange include gaskets or hardware?
This flange is the flange plate only. Exhaust gaskets and header bolts are required separately. See the Kooks SS gasket and BK110 bolt kit listings for compatible hardware.
Is this flange machined flat?
Yes. This flange is precision machined to ensure a flat sealing surface that mates properly with the cylinder head without requiring additional surface preparation in most cases.
How thick is this flange flange?
Contact us for the exact flange thickness specification. A thicker flange provides greater resistance to warping under heat but adds weight. Kooks flanges are designed to balance these properties for performance applications.
Installation Instructions
- Verify this flange matches the bolt hole pattern and port dimensions of your specific LS1 cylinder head before beginning fabrication.
- Clean the cylinder head exhaust port surface and verify it is flat and free of damage.
- Position this flange flange against the cylinder head with the appropriate exhaust gasket in place to confirm fit and alignment.
- Remove the flange from the head and proceed with primary tube fabrication, inserting and tack welding the header primary tubes to the flange port openings.
- After completing the header tube layout, finish weld all primary tube to flange joints using TIG welding with stainless filler.
- Once the header assembly is complete, install it on the cylinder head with the appropriate gasket and torque the header bolts to specification.
Prop 65 Warning
WARNING: This product can expose you to chemicals including Chromium and Nickel, which are known to the State of California to cause cancer, birth defects or reproductive harm. For more information go to www.P65Warnings.ca.gov.
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