Zippers Performance


Zipper’s Stage III CNC Ported Evolution® Heads

SKU# 2399

Availability: In stock

As low as: $1,099.00

Price as configured: $0.00

Quick Overview

Owners of Evolution® powered Big Twins can increase their engine’s output with a set of our CNC-ported EV heads! The factory casting is CNC-machined to our proven high torque, high power port shapes and the valve sizes are increased to 1.900” intake and 1.630” exhaust. Ductile iron Step-Lock guides are fitted and topped off with high quality Viton® seals and a performance spring kit. The head gasket surface is decked for flatness before final assembly. This head has substantially higher low-lift flows for unreal torque increases and is capable of producing over 90 horsepower in an 80” engine (same head used in our 80/80 kit). Requires use of pop-up pistons and possibly additional deck machining for proper compression, depending on your choice of cam and pistons. Spring travel is set for up to .575” valve lift; higher lifts will require an optional spring change.

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+$1,099.00#517-562 Zipper’s Stage III EV-CNC Parts and Labor (customer provided heads)

Price as configured: $0.00

Details

Owners of Evolution® powered Big Twins can increase their engine’s output with a set of our CNC-ported EV heads! The factory casting is CNC-machined to our proven high torque, high power port shapes and the valve sizes are increased to 1.900” intake and 1.630” exhaust. Ductile iron Step-Lock guides are fitted and topped off with high quality Viton® seals and a performance spring kit. The head gasket surface is decked for flatness before final assembly. This head has substantially higher low-lift flows for unreal torque increases and is capable of producing over 90 horsepower in an 80” engine (same head used in our 80/80 kit). Requires use of pop-up pistons and possibly additional deck machining for proper compression, depending on your choice of cam and pistons. Spring travel is set for up to .575” valve lift; higher lifts will require an optional spring change.

Components Include:
  • Full CNC Port and Combustion Chamber Machining
  • Ductile Iron Step-Lock Valve Guides
  • Competition Seat Work on Serdi Equipment
  • 1.900” Int, 1.630” Exh Stainless Steel Valves
  • Performance Valve Springs W/Moly Collars
  • .630” Valve Spring Free Travel
  • 91cc combustion Chamber (Skim Decked)
  • Completely Assembled, Ready To install

Evolution® CNC headwork is performed on supplied head cores; in-house shop time is 10-14 working days

Parts must be in nearly perfect cosmetic condition (box heads individually with lots of newspaper or foam padding!); expect the same from us. Heads that are extremely dirty, stained, etched or have corroded finishes or damaged fins will be processed (10 working days) and returned to you. Remove heads from engine, wash off oil and ship to Zipper’s as-is. Because improper cleaning methods can actually do more harm than good, we suggest you allow us to properly prepare your parts for modification. Extreme care is taken during our preparation process to preserve component finishes. A small cleaning charge applies to exchange heads. Previously modified heads are not eligible for exchange.
The products on this page are not legal for sale or use on pollution-controlled motorcycles.
Learn More About Emissions Compliance.
Zipper’s Stage III CNC Ported Evolution® Heads http://www.zippersperformance.com/media/catalog/product/cache/1/image/265x/9df78eab33525d08d6e5fb8d27136e95/5/1/517-562.jpg Owners of Evolution® powered Big Twins can increase their engine’s output with a set of our CNC-ported EV heads! The factory casting is CNC-machined to our proven high torque, high power port shapes and the valve sizes are increased to 1.900” intake and 1.630” exhaust. Ductile iron Step-Lock guides are fitted and topped off with high quality Viton® seals and a performance spring kit. The head gasket surface is decked for flatness before final assembly. This head has substantially higher low-lift flows for unreal torque increases and is capable of producing over 90 horsepower in an 80” engine (same head used in our 80/80 kit). Requires use of pop-up pistons and possibly additional deck machining for proper compression, depending on your choice of cam and pistons. Spring travel is set for up to .575” valve lift; higher lifts will require an optional spring change.

Components Include:
  • Full CNC Port and Combustion Chamber Machining
  • Ductile Iron Step-Lock Valve Guides
  • Competition Seat Work on Serdi Equipment
  • 1.900” Int, 1.630” Exh Stainless Steel Valves
  • Performance Valve Springs W/Moly Collars
  • .630” Valve Spring Free Travel
  • 91cc combustion Chamber (Skim Decked)
  • Completely Assembled, Ready To install

Evolution® CNC headwork is performed on supplied head cores; in-house shop time is 10-14 working days

Parts must be in nearly perfect cosmetic condition (box heads individually with lots of newspaper or foam padding!); expect the same from us. Heads that are extremely dirty, stained, etched or have corroded finishes or damaged fins will be processed (10 working days) and returned to you. Remove heads from engine, wash off oil and ship to Zipper’s as-is. Because improper cleaning methods can actually do more harm than good, we suggest you allow us to properly prepare your parts for modification. Extreme care is taken during our preparation process to preserve component finishes. A small cleaning charge applies to exchange heads. Previously modified heads are not eligible for exchange.
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