M8 +4MM OVERSIZED (Gen. 1)
The ultimate porting package for riders demanding serious race-level performance. Precision 5-axis work, +4mm valves, and a reshaped CNC chamber deliver up to a +24.27% increase in intake airflow and a +44.4% increase in exhaust flow.
Our M8 +4MM Full Race CNC Porting service is engineered for professional racers and performance enthusiasts who demand serious power from their engines. Leveraging advanced 5-axis CNC technology, this service provides precision-engineered, high-flow ports that unlock your engine’s full potential. The result is one of the most powerful upgrades available, delivering a 24.27% increase in intake airflow and a staggering 44.4% increase in exhaust flow for unmatched power gains and throttle response.
This package is built around massive +4MM oversized stainless steel valves and durable bronze seats, with optional titanium valves available for those seeking the lightest setup for maximum RPM. It also features a fully reshaped CNC combustion chamber for optimized combustion efficiency, a 70mm square intake port modification, and a 2" exhaust flange upgrade to ensure seamless compatibility with other high-performance components.
At Ward Performance, every head undergoes rigorous testing and hand assembly to ensure precise fitment and race-grade reliability. Whether you're chasing records at the track or building the ultimate street machine, our +4MM porting provides a potent, proven upgrade backed by years of expertise in racing and engine development.
Starting at: $3,402.18
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+4MM Oversized Stainless Steel Valves
Engineered for maximum airflow and durability under extreme conditions.
+4MM Oversized Titanium Valves (Optional)
Ultra-lightweight titanium valves for high RPM performance and reduced valve train mass.
Bronze Intake & Exhaust Seats
Essential for achieving the +4MM valve size and ensuring long-lasting reliability.
Extensive 5-Axis CNC Porting
Precision-engineered to optimize intake and exhaust flow for maximum power gains.
70mm Square Intake Port Modification
Enhances airflow compatibility with high-performance intake manifolds.
2" Exhaust Flange Modification
Ensures optimal exhaust flow to match high-output performance systems.
Reshaped CNC Combustion Chamber
Optimized for efficient combustion and tailored compression for your build.
Multi-Radius Competition Valve Job
Delivers smooth airflow through the entire valve lift range for maximum efficiency.
Performance Spring Kits (Optional)
Choose from Steel .640" High-Performance Springs or Ultra-Light Titanium .640" Springs for precise valve control.
Re-Machining of Head Gasket Surface
Ensures a perfect seal for peak performance and longevity.
Professional Assembly & Testing
Each head is thoroughly inspected, assembled, and tested to meet race-grade standards.
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Typically, this service requires you to send in your existing cylinder heads for modification.
For those looking for a quicker option, we offer off-the-shelf core heads that are fully prepared and ready to ship. If you have specific custom needs, we're more than happy to accommodate—just let us know what you're looking for.
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Still have questions or need help deciding?
No worries! We know performance upgrades can be a big decision, and we're here to help.
If you're unsure about anything, don't hesitate to reach out to us or visit our FAQ page for more information. We're just a message away and ready to assist!
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Performance Bronze Valve Guides
High-performance bronze guides are used for durability and precise valve movement.
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Multi-radius Competition Valve Job
Ensures a smooth transition from the valve seat to the inner port, maximizing airflow and enhancing performance.
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High-lift spring kits (.640" lift)
Available in steel or titanium, engineered for optimal valve control in high-performance applications.
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Re-machining of head gasket surface
Ensures perfect sealing and compatibility with your engine setup.
