ZIPPERS PERFORMANCE THUNDERSPORT CYLINDER HEADS HARLEY SPORTSTER

ZIPPERS PERFORMANCE THUNDERSPORT CYLINDER HEADS HARLEY SPORTSTER

SELECT LEVEL OF HEADWORK IN OPTIONS 

THESE ARE AN EXCHANGE ITEM 

STAGE 1-ZP 91+883 STG2 TORKSTER HDWRK

STAGE 2-ZIP 91+883-1200 STG 2.5 HDWORK

STAGE 3-Put a set of our Stage III ThunderSport heads on your Sportster® to really let it breathe! Each port is fully CNC machined for exceptional flow rates; two available combustion chamber sizes are un-shrouded and CNC machined for accuracy in volume. Step-Lock guides are installed and honed to precise size, and seats are radius machined to our proprietary shapes on Serdi equipment for oversized valves of 1.900” and 1.615” diameter (883 heads have all 4 seats replaced to accommodate the larger valves). Viton seals and our Pro-Street springs with Titanium collars are installed to provide proper valve train control. These ThunderSport heads will allow your Sportster® engine to reach its full potential!