S&S CYCLE 129" Power Package Engine Performance Kit — 4.320" bore, 11.0:1 compression, Black – 17-25 Touring, 17-26 Trike

Upgrade your 107" M8 to a 129" powerhouse without case machining — bolt-on kit for straightforward installation.

Big bore 4.320" cylinder with 11.0:1 forged pistons and an HPT496 cam designed for big bore applications deliver improved performance and torque.

S&S oil pump and cam plate feature removable passage plugs, independent scavenge sections for the flywheel cavity and cam chest, and debris screens in both scavenge pickups for cleaner oiling.

A magnet in the cam chest helps prevent debris from entering the oil pump, while increased oil flow capacity and an adjustable pressure relief valve (serviceable installed) ensure reliable lubrication under load.

Includes quickee pushrods with pushrod tubes, S&S premium tappets, hard anodized billet aluminum tappet cuffs, S&S valve springs compatible up to 0.605" lift, MLS head gasket, and a 129 cam cover badge.

The kit retains stock engine height, works with stock crankcases and stock or S&S roller rocker arms, and preserves original engine serial numbers.

Made in the USA.