Cometic C5985-051 GM LS9/LSA MLX Cylinder Head Gasket – 4.100″ Bore, .051″ RHS
The Cometic C5985-051 MLX Cylinder Head Gasket is engineered for GM Gen IV LS9 and LSA supercharged V8 engines, delivering performance-oriented combustion sealing for demanding engine rebuilds and high-cylinder-pressure applications.
Featuring a 4.100-inch gasket bore, .051-inch compressed thickness, and Multi-Layer Steel with an MLX stopper-layer design, this right-hand-side (RHS) cylinder head gasket is intended for compatible GM 6.2L supercharged applications.
Whether you’re rebuilding a Cadillac CTS-V LSA, refreshing a Chevrolet Camaro ZL1, or servicing a Corvette ZR1 LS9, selecting the correct head gasket is essential for maintaining compression, controlling combustion leakage, and preventing coolant and oil contamination.
Key Features and Benefits
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Cometic MLX Technology: Multi-layer steel construction with an engineered stopper layer to concentrate sealing load around the combustion chambers.
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4.100-Inch Gasket Bore: Sized for compatible GM LS9 and LSA engine configurations.
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.051-Inch Compressed Thickness: Provides a defined gasket thickness for accurate engine assembly.
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Right-Hand-Side Configuration: Designed for the specified RHS cylinder bank.
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Forced-Induction Applications: Engineered for demanding supercharged engine environments.
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Precision Sealing: Helps separate combustion pressure, coolant passages, and engine oil.
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Performance Rebuild Compatibility: Suitable for properly prepared stock and modified LS9/LSA engine assemblies.
Technical Specifications
| Specification | Details |
|---|---|
| Manufacturer | Cometic Gasket |
| Part Number | C5985-051 |
| Product Type | Cylinder Head Gasket |
| Engine Family | GM Gen IV Small Block V8 |
| Engine Applications | LS9 / LSA |
| Engine Displacement | 6.2L |
| Construction | MLX Multi-Layer Steel |
| Gasket Bore | 4.100 inches (104.14mm) |
| Compressed Thickness | .051 inches (1.295mm) |
| Cylinder Bank | Right-hand side (RHS) |
| Quantity | 1 head gasket |
| Intended Applications | Supercharged performance engine rebuilds |
Why Choose Cometic MLX for Your Supercharged LS Engine?
The GM LS9 and LSA engines are designed to produce substantial horsepower and torque through factory supercharging. This creates demanding operating conditions for cylinder head gaskets, particularly when pulley changes, increased boost, or engine tuning raise cylinder pressure.
Cometic’s MLX construction incorporates a stopper-layer design that helps concentrate clamping force around the cylinder bores.
This approach is intended to improve combustion sealing in properly assembled high-performance engines.
Unlike a conventional composite head gasket, MLX construction uses engineered steel layers to accommodate thermal cycling and maintain sealing pressure.
Important: Even a premium MLX gasket cannot compensate for improper cylinder head clamping, excessive deck distortion, detonation, or incorrect engine tuning.
$113.99
Year, Make, Model and Engine Fitment
Cometic’s official catalog lists the following applications for C5985-051.
| Years | Make | Model / Trim | Engine |
|---|---|---|---|
| 2009–2015 | Cadillac | CTS-V | 6.2L Supercharged LSA V8 |
| 2012–2015 | Chevrolet | Camaro ZL1 | 6.2L Supercharged LSA V8 |
| 2009–2013 | Chevrolet | Corvette ZR1 | 6.2L Supercharged LS9 V8 |
Fitment warning: This is a right-side gasket. For the corresponding left-side .051-inch MLX gasket, Cometic specifies C5986-051.
FYI: Why Cylinder Head Surface Preparation Matters
Even premium five-layer MLX gaskets require properly prepared sealing surfaces.
Before installing a replacement gasket, check the cylinder head and engine block for flatness, surface damage, and contamination.
Our LS1 Block Deck Warpage Inspection Guide explains how to use a precision straightedge to identify distortion before cylinder head installation. Although written for LS1 engines, the inspection principles are relevant to LS9 and LSA engine rebuilding. Always follow the specific requirements for your engine and gasket.
Frequently Asked Questions
Does the C5985-051 fit the Chevrolet Camaro ZL1?
Yes, Cometic lists the 2012–2015 Camaro application, specifically relevant to the supercharged 6.2L LSA-powered ZL1.
Is this gasket compatible with a Cadillac CTS-V?
Yes, for applicable 2009–2015 CTS-V models equipped with the supercharged LSA V8.
Can I use this on a naturally aspirated LS3?
Do not assume compatibility. Although the LS3 shares certain architecture with the LSA, this part is specifically listed for LS9/LSA applications and has a right-bank-specific configuration.
Does this include both head gaskets?
No. Cometic C5985-051 includes one right-side gasket. Order the matching left-side gasket separately for a complete two-bank replacement.
Specification: Cometic C5985-051 GM LS9/LSA MLX Cylinder Head Gasket – 4.100″ Bore, .051″ RHS
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