Perfect Circle MS909H H-Series Main Bearing Set Small Block Chevy Tri-Metal Standard Size

The Perfect Circle MS909H is a high-performance main bearing set designed for Small Block Chevy engines. Now manufactured under the Clevite/MAHLE brand, this set includes 5 tri-metal bearings engineered for demanding performance applications including racing and high-RPM street engines.

Key Features:

• Tri-metal construction with hardened steel backing, copper-lead alloy layer, and electroplated babbitt overlay for superior strength and durability
• 1/2 groove oil distribution design (180-degree oil groove)
• Standard size bearings for 2.450" main journal crankshafts
• Medium level of eccentricity and high crush factor for optimal heat transfer and resistance to rotation
• Enlarged chamfers for increased crank-fillet clearance, compatible with aftermarket performance crankshafts with larger fillet radius
• No flash tin plating for better seating and improved performance
• Maximum bore: 2.6416", Minimum bore: 2.6406", Maximum wall thickness: 0.095"

Originally developed for NASCAR racing applications, H-Series bearings are ideal for engines operating at medium to high RPM ranges. The distinctive coloration results from the intentional omission of flash plating, which performance engine builders found detrimental to high-output applications. Compatible with Chevy small block engines including 262, 267, 302, 305, 307, 327, and 350 cubic inch displacements.