ZIPPERS PERFORMANCE THUNDERSPORT CYLINDER HEADS HARLEY TC 99-05

ZIPPERS PERFORMANCE THUNDERSPORT CYLINDER HEADS HARLEY TC 99-05

SELECT LEVEL OF HEADWORK IN OPTIONS 

THESE ARE AN EXCHANGE ITEM 

STAGE 1.8-The Stage 1.8 is a fully CNC Ported head designed for 95, 98, 103, or 107 engines. The 1.850” O.S. Valves, new guides and 7mm conical springs. The application allows use with OE piston with shallow valve pockets or engine builder looking for little extra low end response. The head gasket surface will be decked to assure a true/flat sealing surface. Combustion chamber volume is approximately 85-86.5 cc.

STAGE 2-Our Stage II CNC heads employ special high velocity ports developed specifically for riders in search of early torque with broad power. With ports designed for high-velocity airflow, matching these heads with the proper camshaft and exhaust produces amazing power. Perfect for riders of heavier machines who want great acceleration just by turning the throttle – no rowing of the gearbox and high RPM needed!

STAGE 3-Our Stage III ThunderSport heads are the perfect choice for 3.875 – 3.937” bore Twin Cam® engines with all the highs – high compression, high flow throttle body, high flow exhaust and high output at all RPM’s! Our original design has been fully refined to fulfill the airflow needs of the highly modified Twin Cam® engine with displacement ranging from 95 to 107 cubic inches.

STAGE 3.5 MCR-The Zipper’s Performance Stage 3.5 heads with Manual Compression Releases have a special high flow port design that is one of
the largest we can machine into an O.E castings. Special O.S. 2.00” valves, Step Lock Guides, special valve seat machining, 5/16” dual spring for lift up to .675”. These are maximum output heads and are a good option Vs purchasing CVO castings with the added expense of porting. Combustion chambers are 92 cc.