King Engine Bearings MB557GPC010 GPC Race Main Bearing Set GM 262-350 +0.010 In. Undersize

The King Engine Bearings MB557GPC010 is a premium GPC-series tri-metal main bearing set engineered for General Motors small-block engines requiring extreme-load racing performance. Sized at +0.010 in. undersize, these bearings are purpose-built for high-output race engine builds where standard bearing materials simply cannot keep up.

King's GPC technology is a Silver Composite, Polymer Coated tri-metal construction that features an intermediate lead-bronze layer over a steel backing, topped with a silver-based overlay that contains solid lubricant additives distributed throughout the silver matrix. This unique structure delivers exceptional load capacity, rated to handle 17,000 PSI — significantly outperforming conventional race bearing materials that peak at approximately 11,000 PSI, making GPC bearings approximately 30% stronger than other tri-metal competitors.

The factory-applied polymer coating provides a critical additional layer of protection against oil starvation and metal-to-metal contact events common in modified and high-performance race engines. Unlike some aftermarket coatings, King's polymer coating is applied without adding to the bearing's wall thickness, preserving precise clearance specifications.

Key Features:

• GPC tri-metal construction: steel backing, lead-bronze intermediate layer, silver-based overlay
• Lead-free silver overlay with embedded solid lubricant additives for extreme-load applications
• Polymer coating enhances seizure and wear resistance without altering wall thickness
• Rated to 17,000 PSI — surpassing conventional race materials by approximately 55%
• +0.010 in. undersize for use with reground crankshafts
• Designed for high-load racing applications: circle track, drag racing, off-road, and more
• Manufactured to King's industry-leading ±0.0001 in. wall thickness tolerance

The MB557GPC010 is the ideal main bearing choice for serious engine builders constructing a high-performance or all-out race small-block GM engine that demands the highest level of crankshaft protection and load-handling capability.