Enginetech BC364J040 Main Bearings GM 366 396 402 427 454

The Enginetech BC364J040 engine crankshaft main bearing set is a replacement bearing for engine rebuilds. It is sized for crankshaft journals that have been machined .040 inch undersize. Main bearings, also called crankshaft bearings or main bearing shells, support the crankshaft and keep it turning on a thin film of oil.

Key Features:

• .040 undersize (the "040" in the part number) for reground crankshaft journals
• Aluminum-silicon bearing material. Enginetech describes this alloy as performing equal to or better than original tri-metal designs.
• Made by Enginetech, a bearing brand rebuilders have used for more than 25 years
• Direct-replacement main bearing design for GM big-block applications

Measure the journals and check oil clearance with Plastigage before final assembly. This confirms the undersize matches your crankshaft.