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Limited Time Offer S&s Cycle Top End Guardian Kit For 2017-2021 Harley M8 - Ships Same Day [4LlZCzX8]

$76.99 $246.99 -69%

Building your M8 for big power? We've got the parts you need to bulletproof the top end of your valvetrain in one convenient kit! S&S performance parts are direct replacement for OEM pieces, but are stronger and more durable, giving your M8 the r

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Limited Time Offer S&s Cycle Top End Guardian Kit For 2017-2021 Harley M8 - Ships Same Day [4LlZCzX8]

Building your M8 for big power? We've got the parts you need to bulletproof the top end of your valvetrain in one convenient kit! S&S performance parts are direct replacement for OEM pieces, but are stronger and more durable, giving your M8 the reliability it needs as you build big HP and Torque numbers. Rocker Arm shafts, Rocker Arm Stud Kit, Head Bolt Kit and Performance Roller Rocker Arms are included in this kit that is the perfect topper for your high performance M8 build

Rocker Arm Shafts
  • Replace broken or worn OEM pieces with stronger, more durable S&S performance parts
  • Direct replacement for stock parts
  • Hardened and surface ground for ultimate precision and durability
Rocker Arm Stud Kit
  • Extend the life of your cylinder heads
  • Prevent damage to Rocker Arm Towers
  • Install studs and safely re-torque nuts
  • Black Oxide Finish
  • 12 pt Nuts
Head Bolt Kit
  • Heat Treated 8640 Steel
  • 200,000 psi Ultimate Tensile Strength
  • 14% increases in strength over stock
  • Stronger material than stock Head bolts
  • Durable Black Oxide Coating
  • 9/16" 12 point head with integral washer
  • Formed threads
  • Cold Formed Head
  • Reusable
Forged Roller Rocker Arms
  • Forged from 8620 steel for greater strength
  • Designed using Finite Element Analysis (FEA)
  • Rollers eliminate thrusting on valves for decreased wear on the valve train
  • Rocker geometry is better suited to high lift cams
  • Bushings are 50% longer than stock, increasing time between rebuilds
  • Larger surface area on the thrust surfaces reduces wear on the heads
  • Oil is sprayed directly on the valve springs, reducing potential for breaking a valve due to over-heating (stock rockers tend to oil the rocker boxes, not the valves)
  • Compatible with stock or S&S CNC heads
  • 1.640 Ratio
  • Capable of .650" max Valve Lift
  • Serviceable and rebuildable for generations of durabilty
  • A must have for cams with .550" or greater lift!

What Our Customers Say

January 23, 2026

Absolutely no complaints!

A great product. And very, very good.

- Tamica N..

January 23, 2026

Absolutely no complaints!

This is a very, very useful item.

- Ethel H..

January 23, 2026

Absolutely no complaints!

A product that instills total confidence.

- Abigail V..

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