Perfect Circle MS829H21 H-Series Main Bearing Set .021 Oversize Big Block Chevy

The Perfect Circle MS829H21 is a high-performance crankshaft main bearing set designed for big block Chevrolet engines including 366, 396, 402, 427, 454, and 502 cubic inch applications. This bearing set features .021 inch oversize dimensions for use with crankshafts that have been machined undersize.

H-Series Performance Features:

• Tri-metal construction with precision steel backing, copper-lead alloy intermediate layer, and thin electroplated babbitt overlay
• Medium level of eccentricity with high crush factor for secure retention
• Enlarged chamfers for greater crankshaft fillet clearance
• Manufactured without flash plating for improved seating and contact
• Hardened steel back with thin overlay reduces friction and drag
• Half-groove design for optimized oil distribution

Originally developed for NASCAR racing applications, H-Series bearings are well-suited for all types of competition engines and high-performance builds that operate in the medium to high RPM range. The set includes five bearing pairs plus thrust bearing components. These bearings are ideal for engines with crankshafts featuring oversize fillets and demanding performance requirements.