Clevite MS-1266HG High Performance Main Bearing Set with Full Groove

The Clevite MS-1266HG is a high-performance main bearing set featuring full 360-degree grooving designed to maximize oil flow to connecting rod bearings in demanding racing applications. This bearing set combines proven TriMetal construction with specifications optimized for competition engines.

H-Series Performance Features:

• Medium eccentricity design for optimal contact patterns covering 2/3 to 3/4 of bearing surface
• Full 360-degree upper shell grooving (HG designation) for maximum oil delivery to rod bearings
• High crush design ensures maximum bearing retention under extreme conditions
• Hardened steel backing provides superior strength and fretting resistance
• Thin overlay construction prevents overlay fatigue and hen tracking
• Enlarged chamfers accommodate oversize crankshaft fillets
• Non-flash plated for improved bearing seating and break-in

Application Guidelines:

H-Series bearings were developed primarily for NASCAR-style racing but are suitable for all competition engines running in medium to high RPM ranges. The full groove (HG) configuration in this set provides enhanced oil flow compared to standard 180-degree grooved designs, making it ideal for applications where connecting rod bearing oil starvation is a concern. These bearings work best with crankshafts featuring oversize fillets and in engines requiring maximum lubrication delivery to rod bearings.

The MS-1266HG utilizes Clevite's legendary TriMetal bearing construction with lead-tin-copper overlay, offering an excellent balance of durability, wear resistance, and conformability for high-performance applications. If you're unsure which performance bearing series to choose, H-Series bearings represent the best starting point for most competition builds.