King SI-Series Main Bearings

4.03 out of 5 stars 86 Customer Reviews

King SI-Series main bearings are recommended for OE applications. These replacement bearings are designed for aftermarket gasoline or diesel engine rebuilding—and performance engines with factory crankshafts. The bearings have an improved crankshaft finish for reducing microscopic ferrite peaks on improperly ground or polished nodular cast iron crankshafts. King SI-Series main bearings feature improved oil clearance to reduce wear and increase engine life, which in turn reduces operating noise, vibration, and excess oil flow. Order the bearing set designed for fitment on your make and model.

Showing In Stock Items. Show All 21 Items.

Results 1 - 15 of 15

King SI-Series Main Bearings MB 557SI

Main Bearings, 1/2 Groove, Standard Size, Bi-metal, Silicon Aluminum, Chevy, Small Block, Set of 5

Part Number: KGB-MB557SI

4.0 out of 5 stars ( 9 )

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 557SI 010

Main Bearings, 1/2 Groove, .010 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, Chevy, Small Block, Set of 5

Part Number: KGB-MB557SI010

4.67 out of 5 stars ( 6 )

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 557SI 001

Main Bearings, 1/2 Groove, .001 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, Chevy, Small Block, Set of 5

Part Number: KGB-MB557SI001

5.0 out of 5 stars ( 2 )

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 557SI 020

Main Bearings, 1/2 Groove, .020 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, Chevy, Small Block, Set of 5

Part Number: KGB-MB557SI020

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 557SI 030

Main Bearings, 1/2 Groove, .030 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, Chevy, Small Block, Set of 5

Part Number: KGB-MB557SI030

1.0 out of 5 stars ( 1 )

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 557SI 040

Main Bearings, 1/2 Groove, .040 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, Chevy, Small Block, Set of 5

Part Number: KGB-MB557SI040

Not Yet Reviewed

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 558SI 010

Main Bearings, 1/2 Groove, .010 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, Dodge, Plymouth, V8, Set of 5

Part Number: KGB-MB558SI010

Not Yet Reviewed

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 557SISTDX

Main Bearings, 1/2 Groove, .001 in. Thinner, Bi-metal, Silicon Aluminum, Chevy, Small Block, Set of 5

Part Number: KGB-MB557SISTDX

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 445SI 010

Main Bearings, 1/2 Groove, .010 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, GM V6, Set of 5

Part Number: KGB-MB445SI010

Not Yet Reviewed

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 752SI 010

Main Bearing Set

Part Number: KGB-MB752SI010

Not Yet Reviewed

Estimated Ship Date: Apr 30, 2026 if ordered today

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Estimated Ship Date: Apr 30, 2026 if ordered today

King SI-Series Main Bearings MB 445SI 001

Main Bearings, 1/2 Groove, .001 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, GM V6, Set of 5

Part Number: KGB-MB445SI001

Not Yet Reviewed

Estimated Ship Date: Apr 28, 2026 if ordered today

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Estimated Ship Date: Apr 28, 2026 if ordered today

King SI-Series Main Bearings MB 445SI 020

Main Bearings, 1/2 Groove, .020 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, GM V6, Set of 5

Part Number: KGB-MB445SI020

5.0 out of 5 stars ( 1 )

Estimated Ship Date: Monday 2/2/2026

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Estimated Ship Date: Monday 2/2/2026

King SI-Series Main Bearings MB 445SI 030

Main Bearings, 1/2 Groove, .030 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, GM V6, Set of 5

Part Number: KGB-MB445SI030

Not Yet Reviewed

Estimated Ship Date: Apr 28, 2026 if ordered today

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Estimated Ship Date: Apr 28, 2026 if ordered today

King SI-Series Main Bearings MB4530SI

Main Bearings, King SI-Series Main Bearings, Stock Size, Bi-Metal, Chevy, Sold as a Set of 4

Part Number: KGB-MB4530SI

Not Yet Reviewed

Estimated Ship Date: Apr 30, 2026 if ordered today

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Estimated Ship Date: Apr 30, 2026 if ordered today

King SI-Series Main Bearings MB 445SI 040

Main Bearings, 1/2 Groove, .040 in. Crankshaft Undersize, Bi-metal, Silicon Aluminum, GM V6, Set of 5

Part Number: KGB-MB445SI040

Not Yet Reviewed

Estimated Ship Date: Apr 29, 2026 if ordered today

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Estimated Ship Date: Apr 29, 2026 if ordered today

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