Cometic C5475-040 LS MLS Head Gaskets (Pair) – 3.910″ Bore, .040″ Thickness
Performance Head Gaskets for GM LS 4.8L, 5.3L and 5.7L V8 Engines
Build your GM LS engine with dependable cylinder head sealing using this pair of Cometic C5475-040 Multi-Layer Steel (MLS) Head Gaskets.
Featuring a precision-engineered 3.910-inch gasket bore and .040-inch compressed thickness, these gaskets are designed for compatible GM Generation III and IV LS-family engines, including select LS1, LS6, LR4, LM7, L59, L33, LC9, LMG, LMF, LS4, and L20 applications.
Whether you’re rebuilding an LS1 Camaro, refreshing a 5.3L Silverado engine, or preparing an LS-powered project for forced induction, Cometic MLS gaskets provide a durable sealing solution when paired with proper engine preparation and cylinder head clamping.
Sold as a pair: Includes two Cometic C5475-040 cylinder head gaskets, one for each bank of a compatible V8 engine.
Key Features and Benefits
- Complete Pair: Two head gaskets for both cylinder banks.
- Multi-Layer Steel Construction: Three stainless steel layers provide strength, resilience, and corrosion resistance.
- 3.910-Inch Gasket Bore: Suitable for compatible LS-family engines with appropriately sized cylinder bores.
- .040-Inch Compressed Thickness: Allows precise calculations of compression ratio and piston-to-head clearance.
- Embossed Sealing Layers: Designed to maintain combustion sealing around cylinder openings.
- Performance Applications: Suitable for properly engineered naturally aspirated and forced-induction builds.
- Precision Manufacturing: Designed for consistent sealing and clamping-load distribution.
Technical Specifications
| Specification | Details |
|---|---|
| Brand | Cometic Gasket |
| Manufacturer Part Number | C5475-040 |
| Product Type | MLS Cylinder Head Gasket Pair |
| Engine Family | GM Gen III / IV LS V8 |
| Gasket Bore | 3.910 inches / 99.31mm |
| Compressed Thickness | .040 inches / 1.016mm |
| Material | Multi-Layer Stainless Steel |
| Number of Layers | 3 |
| Bore Shape | Round |
| Gasket Orientation | Non-Directional |
| Package Quantity | 2 Gaskets (Retailer Bundle) |
| Manufacturer Package Quantity | 1 Gasket Each |
| UPC Per Individual Gasket | 191070008772 |
$209.99
Year, Make, Model & Engine Fitment
The following are common compatible LS-family vehicle applications. Always verify the exact engine code, finished cylinder bore, and head configuration.
| Years | Make | Model | Engine |
|---|---|---|---|
| 1998–2002 | Chevrolet | Camaro Z28 / SS | 5.7L LS1 |
| 1997–2004 | Chevrolet | Corvette | 5.7L LS1 |
| 2001–2004 | Chevrolet | Corvette Z06 | 5.7L LS6 |
| 1998–2002 | Pontiac | Firebird Formula / Trans Am | 5.7L LS1 |
| 2004 | Pontiac | GTO | 5.7L LS1 |
| 1999–2013 | Chevrolet | Silverado 1500 | Select 4.8L / 5.3L V8 |
| 1999–2013 | GMC | Sierra 1500 | Select 4.8L / 5.3L V8 |
| 2000–2014 | Chevrolet | Tahoe | Select 4.8L / 5.3L V8 |
| 2000–2014 | Chevrolet | Suburban 1500 | Select 5.3L V8 |
| 2000–2014 | GMC | Yukon / Yukon XL 1500 | Select 4.8L / 5.3L V8 |
| 2002–2013 | Chevrolet | Avalanche / Avalanche 1500 | Select 5.3L V8 |
| 2003–2006 | Chevrolet | TrailBlazer EXT | Select 5.3L V8 |
| 2005–2009 | GMC | Envoy | Select 5.3L V8 |
| 2006–2009 | Chevrolet | Impala SS | 5.3L LS4 |
| 2006–2007 | Chevrolet | Monte Carlo SS | 5.3L LS4 |
| 2005–2008 | Pontiac | Grand Prix GXP | 5.3L LS4 |
| 2008–2009 | Buick | LaCrosse Super | 5.3L LS4 |
Fitment warning: Vehicle production ranges do not mean every engine or trim is compatible. Do not use this 3.910-inch gasket on engines with cylinder bores larger than the gasket opening.
Why Choose Cometic MLS Head Gaskets?
GM LS engines are popular for their durability, performance potential, and extensive aftermarket support. However, reliable cylinder head sealing becomes especially important when increasing compression, boost, or combustion pressure.
The Cometic C5475-040 uses three stainless steel layers with embossed sealing surfaces to help maintain consistent contact pressure between the cylinder head and engine block.
Its .040-inch compressed thickness also makes it an important component in engine assembly calculations.
FYI: Gasket Thickness and LS Engine Compression
Changing head gasket thickness affects the volume above the piston at top dead center.
A thinner gasket can reduce clearance volume and increase static compression compared with a thicker gasket, assuming all other dimensions remain unchanged.
However, engine builders must also consider piston-to-head clearance, piston-to-valve clearance, cylinder head design, and combustion chamber dimensions.
For related technical information, read How to Check LS1 Block Deck Warpage and LS1 Piston-to-Deck Clearance.
Installation Recommendations
- Identify the engine code and measure the finished cylinder bore.
- Verify gasket compatibility with the block and cylinder heads.
- Check the cylinder head and block deck for warpage.
- Confirm the mating-surface finish meets Cometic MLS requirements.
- Thoroughly clean both sealing surfaces.
- Install the gaskets dry unless Cometic specifies otherwise.
- Use appropriate new head bolts or compatible studs.
- Follow the fastener manufacturer’s tightening procedure.
- Verify engine timing and complete reassembly.
- Pressure-test or inspect the cooling system for leaks.
Frequently Asked Questions
Does this pair fit a 2002 Camaro LS1?
Yes, for a compatible stock-bore or appropriately configured LS1 engine.
Will these gaskets work on a 5.3L Silverado?
They are listed for select 5.3L LS-family applications. Confirm the exact engine and gasket configuration before installation.
Do these fit an LS3 or 6.0L LQ4?
No. The factory bores of those engines are larger than 3.910 inches. Choose a gasket with the correct opening.
Are two gaskets included?
Yes, this Pro Street Online bundle is described as containing two individual C5475-040 gaskets.
Can I use these gaskets for a turbocharged LS build?
Potentially, provided the engine dimensions, surface preparation, cylinder head fasteners, and tuning are appropriate.
Complete Your LS Engine Rebuild
The Cometic C5475-040 MLS Head Gasket Pair provides two stainless steel cylinder head gaskets with a 3.910-inch bore and .040-inch compressed thickness for compatible GM LS V8 engines.
Whether you’re rebuilding an LS1 sports car engine or upgrading a 5.3L truck motor, proper head gasket selection helps establish a reliable foundation for your build.
Shop performance engine components at Pro Street Online.
Specification: Cometic C5475-040 LS MLS Head Gaskets (Pair) – 3.910″ Bore, .040″ Thickness
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