What is the purpose of main bearings in an engine?

Main bearings support the crankshaft within the engine block. They create a low-friction surface for the crankshaft to rotate on, and they are critical for maintaining proper oil pressure and engine health.

What does the 'SI' in the part number MB5877SI typically indicate?

The 'SI' suffix in King Engine Bearings part numbers often refers to their 'Super Inconel' overlay, which is a high-performance bearing material designed for enhanced durability and performance.

Are these bearings suitable for a high-performance or racing application?

King Engine Bearings are known for their robust construction and are often used in performance applications. However, for specific racing needs, it's always best to consult with a performance engine builder to ensure they meet your exact requirements.

Specifications

Brand: King Engine Bearings
Part #: MB5877SI
UPC: 611500626784

King Engine Bearings GM Vortex / Gen III IV LS-Series Main Bearing Set

Name: King Engine Bearings GM Vortex / Gen III IV LS-Series Main Bearing Set
Brand: King Engine Bearings
SKU: king-engine-bearings-king-engine-bearings-gm-vortex-gen-iii-iv-ls-series-main-be-t14-888577
Price: 94.85 USD
Availability: BackOrder

$94.85

On Backorder — Expected to ship by Sep 16, 2026

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

King Engine Bearings LS-Series Main Bearing Set MB5877SI. Get a solid option for your GM Vortex, Gen III, or Gen IV LS engine.

Key Features

This product is a King Engine Bearings GM Vortex / Gen III IV LS-Series Main Bearing Set.
Includes the main bearings required for a GM Vortex, Gen III, or Gen IV LS-series engine rebuild.
Designed to fit the LS engine platform for straightforward installation.
A well-built option for supporting your engine's crankshaft.

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About this part

Product Details

When you're rebuilding the bottom end of your GM Vortex, Gen III, or Gen IV LS-series engine, a good set of main bearings is crucial. This set from King Engine Bearings, part number MB5877SI, gives you the main bearings needed to get your crankshaft properly supported and spinning smoothly.

King has been around for a while, and they make well-built bearings. This set is designed to fit right into the LS engine platform, which means you can get your build back on track without a lot of fuss. Proper bearing clearance is key for oil pressure and longevity, and these bearings are made to meet those needs for your rebuild.