HKS 03-06 Evo 8/9 1.2mm Stopper head gasket (86mm bore 8.5 cr) HKS HKS23001-AM004
HKS 03-06 Evo 8/9 1.2mm Stopper head gasket (86mm bore 8.5 cr) HKS HKS23001-AM004
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HKS 03-06 Evo 8/9 1.2mm Stopper head gasket (86mm bore 8.5 cr)

HKS
HKS23001-AM004
4957266643020
Head Gaskets
7 Units In Stock - Ships Next Business Day
$ 330.00
FREE Ground Shipping!
$ 330.00

SKU: 23001-AM004 | UPC: 4957266643020

HKS 03-06 Evo 8/9 1.2mm Stopper Head Gasket (86mm Bore 8.5 CR)

This HKS Stopper Head Gasket provides exact compression control for 2003-2006 Mitsubishi Lancer Evolution 8 and 9 with 4G63T engines. The 1.2mm thickness and 86mm bore deliver 8.5:1 compression ratio suited to turbocharged performance builds. Stopper construction holds seal under boost pressures exceeding 30 psi in Evo racing applications.

Key Features

  • Stopper Layer Construction: Reinforced center layer prevents blowout and seals during high cylinder pressures over 30 psi boost
  • 1.2mm Thickness: Engineered to achieve 8.5:1 compression ratio with stock head or aftermarket parts
  • 86mm Bore Diameter: Matches Evo 4G63 pistons for correct combustion chamber volume and power delivery
  • Multi-Layer Steel Build: Three-layer MLS material resists heat and allows reuse in track environments
  • HKS Precision Machining: Tolerances under 0.01mm ensure head-to-block fit that minimizes leaks and improves efficiency

Product Notes

  • Inspect and machine cylinder head and block surfaces to ensure flatness within 0.002 inches prior to installation
  • Torque head bolts in sequence using moly paste and follow HKS or ARP specifications for longevity
  • Store flat in original packaging away from moisture to preserve sealing edges

Installation Notes

  • Professional installation recommended.
  • Requires complete cylinder head removal and resurfacing for best results
  • Compatible with HKS head studs or ARP 625+ kit for secure clamping under high boost

This Part Fits

Year Make Model Submodel
2003-2005 Mitsubishi Lancer Evolution VIII (RS GSR MR FQ-300 FQ-360)
2005-2006 Mitsubishi Lancer Evolution IX (RS GSR MR FQ-360)

Why Choose HKS?

  • Proven in Super Taikyu and D1GP racing with Evo platforms for over 20 years
  • Manufactured in Japan with aerospace-grade materials for consistent high-RPM durability
  • Backed by dyno-tested data showing 10% power gains in boosted 4G63 applications

Frequently Asked Questions

  • Q: Will this gasket fit 2006 Evo 9 MR with stock pistons?
    A: Yes it directly fits all 2003-2006 Evo 8/9 variants including MR models with 86mm bore 4G63T engines for immediate 8.5:1 CR upgrade
  • Q: What material makes up the gasket layers?
    A: Triple-layer stainless steel with solid stopper bead and elastomeric coating for superior heat cycle resistance up to 1000 degrees F
  • Q: Does HKS offer a warranty on this head gasket?
    A: Covered under HKS limited lifetime warranty against manufacturing defects when installed by certified technicians

Shipping & Handling

  • Method: UPS Ground or USPS Priority
  • Availability: In stock - ships same or next business day
  • Packaging: Protective flat envelope 12 x 9 x 0.5 inches
  • Weight: 0.35 lbs

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