Similar to the Stage 3 head, this fully developed CNC ported head has excellent flow that makes huge improvements required for large displacement M8 engines. This design has improved velocity helps make excellent early torque and peak HP.

For use on big bore M8 engines. O.S. valves sizes + 1.5mm intake 41.5/33 +1mm exhaust. Requires O.S. Induction

• CNC Porting Improves Bowl & Short-Turn Flow
• Oversize 41.5mm Intake, 33mm Exhaust Valves
• 345 CFM Intake Port Flow
• 202 CFM Exhaust Port Flow
• Precision Valve Height Matching
• Competition Valve Job with De-Shrouding for Improved Flow
• Decking to Achieve 92.5cc Combustion Chamber
• Performance Valve Springs Set Up for Cam
• Custom decked for your specific application
• Best quality workmanship and materials used
• Supports 140+HP/TQ On 4.125-4.250″ Bore Engines

Work is performed on your supplied head cores. Once heads are received at Zipper’s, Shop Time is approximately 15 business days (during peak season allow for additional time). Exchange heads may be available if the condition of your cores qualifies. Currently we do not offer M8 cores for sale. Please send your cores in for processing or exchange.

International Customers – Import duties are not required when shipping your castings for modification. Special low shipping rates are available for your cores; contact your sales representative for details.

Remove heads from engine, wash off oil and ship to Zipper’s as-is. Improper cleaning methods can actually do more harm than good; we suggest you allow us to properly prepare your heads for modification. Extreme care is taken during our preparation process to preserve component finishes.



Zipper’s Engine & Powertrain Service Request


This product is not for sale or use on pollution controlled vehicles.

Weight 1 lbs

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