ACL Bearings 5M1038HX-STD Main Bearing Set for Small Block Chevy 400

The ACL Bearings 5M1038HX-STD is a high-performance main bearing set engineered for Small Block Chevrolet 400 cubic inch V8 engines. Part of ACL's Race Series H-Series lineup, this bearing set features trimetal construction designed to withstand extreme RPM conditions and elevated operating temperatures.

Key Features:

• Trimetal construction with three layers of hardened steel, copper, and nickel for superior strength and reduced friction
• HX-STD sizing provides an extra .001" (0.025mm) oil clearance compared to standard H-Series bearings
• High-strength overlay plate with reduced thickness for improved fatigue resistance
• Hardened steel backing improves bearing support and retention in the housing
• Elimination of flash plating on bearing backs for improved heat transfer and maximum grip
• Increased eccentricity compensates for bore distortion at high RPM
• Tight, consistent wall tolerances for reliable clearance control
• Standard crankshaft journal size: 2.6484" - 2.6493" (67.269mm - 67.292mm)
• Standard tunnel size: 2.8406" - 2.8415" (72.151mm - 72.174mm)

The HX-STD designation indicates this bearing set is optimized for high to extreme power applications where additional oil clearance is beneficial to component reliability and longevity. The trimetal composition substantially lowers friction while reducing operating temperatures and providing superior lubrication characteristics essential for racing and high-performance street applications.