Zipper’s Muscle 124 kit delivers 140+ Twin Cam® HP & Torque!  A new 4-5/8” stroke crankshaft replaces the original 4” crank; new stress-relieved 4-1/8” bore cylinders are precision fit with forged pistons set for 10.75:1 compression. Your heads receive Zipper’s Stage IV CNC porting with highly modified chambers, 2.0” intake, 1.630” exhaust valves, performance springs. Our Red Shift 657 cams provide stunning torque & HP gains across the entire RPM range. Also included are Pro-Taper pushrods and EZ-Adjust covers, with all gaskets needed for assembly. Highly recommended option: Zipper’s #417-495 blueprinted cam chest upgrade with our Red Shift Dual Piston hydraulic cam chain tensioners, blueprinted billet plate, HV oil pump, cam bearings and quality USA lifters for improved reliability and durability. Case boring, Timken conversion required.  CVO? M8? Make them all believers with Zipper’s Muscle 124 Twin Cam®!

This kit uses your factory head cores sent in for modification. An exchange may be possible once your cores are cleaned, inspected and qualified for exchange.


Not legal for sale or use in California on any pollution controlled motor vehicle.
Not legal for sale or use on any EPA pollution controlled motor vehicle.

*To ensure you enjoy a premium experience, Please fill out a Build Sheet/Job Order Sheet prior to completing an order on the website.
Click here for Zipper’s Build Sheet/Job Order Sheet

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