Michigan Motorsports LS Main Crank Bearings Standard Size SI-Series — Complete 5-Bearing Kit, Bi-Metal Construction

Refresh or upgrade the bottom end of an LS engine with a purpose-built bearing set designed for reliability and predictable oil clearance. This SI-Series kit was created for the common 4.8L, 5.3L, 5.7L, 6.0L and 6.2L LS platforms and includes all five main bearings required for a full installation. The bearings use a bi-metal silicon-aluminum construction that balances load support with durable wear resistance, making them suitable for stock rebuilds, street performance upgrades, and LS swap projects where the factory crankshaft is retained.

Will these bearings fit my Gen III/Gen IV LS engine?

Yes — the set is intended for standard-size mains on most LS family engines that use original crankshaft journal diameters. It covers a wide list of popular engine codes across cars, trucks, and SUVs.

• Compatible with LS1, LS2, LS3, LS6 and many truck-based blocks
• Fits LQ4, LQ9, L92, L94, L76, L77, LY6, L96 and similar castings
• Supplied as a full five-bearing set for complete rebuilds

How does the SI-Series design help engine longevity?

The bearing construction combines a supporting steel-backed layer with a silicon-aluminum alloy running surface to resist wear while maintaining necessary conformability. That combination helps the bearing accommodate small surface irregularities on nodular iron crank journals and preserves oil film integrity under load.

• Bi-metal construction improves load capacity and wear resistance
• Maintains proper oil clearance to protect journal surfaces
• Helps smooth microscopic crankshaft imperfections for quieter operation

Are these bearings suitable for performance builds or only stock rebuilds?

They are engineered to serve both stock rebuilds and many street-performance applications that retain an OEM crankshaft. The SI-Series focuses on delivering predictable clearance, durability, and consistent behavior under typical operating conditions rather than extreme racing stress.

• Ideal for stock refreshes, everyday drivers, and mild performance upgrades
• Works with factory crankshafts—no custom machining required for standard-size journals
• Not intended for high-horsepower engines requiring specialty oversized or coated bearings

What comes in the package and what should I check during installation?

The kit includes five standard-size main bearings to outfit the crankshaft main journals. During installation, verify journal diameter, measure oil clearances with plastigauge or micrometers, and follow torque specs and lubrication procedures for break-in.

• Complete five-bearing set for full main cap coverage
• Confirm crank journal size and bearing orientation before final assembly
• Use proper assembly lube and check clearances to OEM tolerances

Who is this for: This bearing set is aimed at mechanics, hobbyists, and engine builders refreshing Gen III/IV LS engines who plan to retain the factory crankshaft. It fits restorations, street-driven performance rebuilds, and common LS swap projects where dependable, standard-size main bearings are required. If you need oversized, coated, or race-specific bearings, choose a specialized product; for reliable OEM-dimension rebuilds and many performance applications, this Michigan Motorsports SI-Series set is a practical choice.