S&S CYCLE 129" Power Package Engine Performance Kit — 4.320" bore, 11.0:1 compression – 18-26 Softail, 25 Touring, 17-25 Trike

The S&S 129" Power Package bolt-on big bore kit increases a 107" M8 to 129" without case machining, retaining stock engine height.

It features a big bore 4.320" cylinder with 11.0:1 forged pistons and an MLS head gasket, plus the HPT496 cam optimized for big bore applications.

S&S oil pump with cam plate, independent scavenge sections for the flywheel cavity and cam chest, debris screens in both pickups, and a magnet in the cam chest help protect the oil system.

Increased oil flow on both feed and scavenge sides, and an adjustable pressure relief valve that can be set with the unit installed, make this kit service-friendly.

Includes Quickee pushrods with pushrod tubes, S&S premium tappets, hard-anodized billet tappet cuffs, S&S valve springs (compatible with cams up to 0.605" lift), and a 129 cam cover badge.

Works with stock crankcases and roller rocker arms, retains original engine serial numbers, and is made in the USA.