King Engine Bearings MB5557SI0.25 Main Bearing Set for Chevrolet 121ci LN2 134ci

The King Engine Bearings MB5557SI0.25 is a precision-engineered main bearing set designed specifically for Chevrolet 121 cubic inch and LN2 134 cubic inch engines. This oversize bearing set features a 0.25mm (0.010") oversize dimension, making it ideal for engines that have had their crankshaft journals machined during rebuilds or performance upgrades.

Construction and Material Technology:

• Bi-metal construction with silicon aluminum alloy bearing surface
• Aluminum-based material strengthened with 2.5-3% silicon content for enhanced durability
• Engineered for medium-load applications and nodular cast iron crankshafts
• Superior conformability and embeddability compared to traditional bearing materials
• Excellent heat dissipation properties to maintain optimal operating temperatures

Key Features:

• 0.25mm (0.010") oversize for machined crankshaft journals
• Complete main bearing set for comprehensive engine rebuild
• Manufactured to OEM specifications with tight tolerances
• Compatible with stock and mild performance applications
• Protective coating to prevent corrosion during storage and installation

King Engine Bearings are known for their precision manufacturing and quality control processes, ensuring proper oil clearances and reliable performance. The silicon-aluminum alloy construction provides an excellent balance of strength, wear resistance, and compatibility with nodular iron crankshafts commonly found in these Chevrolet engines.