16x Intake Guides16x Exhaust Guides

Each BMW S63 Head Stud Thread Insert Kit includes:

Built for racing and high-performance applications

Derived from the acclaimed 129 Series

By choosing the long rod kit

S58 Billet Main Caps by 5150 AutoSport X4 G02 16x Intake Guides16x Exhaust Guides5150 AutoSport S58 Billet Main Caps As power levels climb beyond 1,200+ horsepower, we've seen factory main caps begin to walk. Under extreme cylinder pressure and crankshaft loads, even the slightest cap movement can affect main bearing alignment, oil clearance, and ultimately bearing life. Our CNC machined billet steel main caps are heat treated for maximum strength and feature a dowel pinned design to positively locate each cap and virtually