Designed for Machined LS Crankshafts

These .010” undersize main bearings are intended for LS crankshafts that have been machined .010 inch undersized during the rebuilding process.

The SI-Series bearings are compatible with popular LS engine platforms including:

• LS1
• LS2
• LS3
• LQ4
• LQ9
• L92
• L94
• L76
• L77
• LY6
• L96

Supported engine sizes include:

• 4.8L
• 5.3L
• 5.7L
• 6.0L
• 6.2L

This wide fitment makes the bearings suitable for both Gen III and Gen IV LS engine projects. Learn what makes the LS engines different with this guide.

The Michigan Motorsports LS Main Crank Bearings .010″ Undersize SI-Series are designed to deliver durability and precision for both stock and performance LS builds.

Critical Support for Crankshaft Stability

Main bearings are responsible for supporting the crankshaft within the engine block while maintaining proper oil clearance under load.

High-quality main bearings help provide:

• Stable oil pressure
• Reduced crankshaft friction
• Proper lubrication between rotating surfaces
• Improved durability under load
• Reliable engine operation at higher RPM

In performance applications, proper bearing clearance becomes even more important due to increased cylinder pressure, elevated RPM, and additional heat generated by turbocharging or aggressive tuning.

Manufactured with high-quality bi-metal silicon aluminum materials, these bearings provide superior wear resistance, improved oil clearance, and reduced noise and vibration in comparison to factory designs.

Built for LS Enthusiasts and Engine Builders

Michigan Motorsports has become a respected source for LS engine components, swap hardware, and performance rebuild parts trusted by enthusiasts and professional builders alike.

Their LS-focused product lineup supports:

• Street performance builds
• Racing applications
• OEM-style rebuilds
• DIY LS swaps
• High-horsepower forced induction setups

The SI-Series .010” undersize main bearings continue that reputation by offering dependable crankshaft support for a wide variety of LS engine combinations.

Perfect to be used with factory crankshafts which were turned .010″, they be certain that proper fitment and reliability in the whole lot from day-to-day drivers to boosted or high-horsepower performance engines. Whether you’re rebuilding an LS1, LS2, LS3, LQ4, LQ9, or other popular GM LS-based engine, these SI-Series main bearings deliver consistent performance and long engine life.

Ideal for Performance and Rebuild Applications

The Michigan Motorsports SI-Series bearings are designed for use in:

• Stock LS rebuilds
• Performance street engines
• Turbocharged LS setups
• Supercharged applications
• Drift and drag builds
• Engine swap projects

Whether you’re rebuilding a budget junkyard 6.0L or assembling a high-horsepower LS3 setup, fresh main bearings are one of the most important investments in long-term engine reliability.

Engineered for Stock & Performance Builds – Designed for both factory rebuilds and high-performance LS applications, these .010″ undersize main bearings be certain that reliability and durability whether in a street-driven vehicle or a boosted race build.
Premium SI-Series Construction – Manufactured from a bi-metal silicon aluminum alloy, these bearings provide exceptional wear resistance, better heat dissipation, and improved surface contact for long-lasting performance under demanding conditions.
Designed for Turned Crankshafts – Specifically engineered for crankshafts which were machined .010″ undersize, guaranteeing proper oil clearance, reduced friction, and maximum efficiency for your LS engine rebuild.
Improved Oil Keep watch over & Longevity – Enhanced design helps deal with consistent oil film thickness, reducing noise, vibration, and excess oil waft, which extends overall engine life at the same time as supporting higher horsepower levels.
Wide LS Engine Compatibility – Fits a broad range of GM Gen III and Gen IV LS-based V8 engines, including LS1, LS2, LS3, LQ4, LQ9, L92, L94, L76, L77, LY6, and L96 in 4.8L, 5.3L, 5.7L, 6.0L, and 6.2L configurations.

Why Proper Bearing Selection Matters

Incorrect bearing sizing can lead to:

• Oil starvation
• Low oil pressure
• Excessive crankshaft wear
• Bearing failure
• Complete engine damage

Using properly sized undersize bearings after crankshaft machining helps restore correct oil clearances and maintain reliable engine operation.

Because nothing empties a project budget faster than hearing your fresh LS rebuild suddenly develop percussion instruments inside the oil pan.