This GLYCO main bearing, part number 71-3904, is designed to meet the exacting standards required for engine rebuilding. Manufactured with high-quality materials, it ensures reliable support for the crankshaft, contributing to smooth engine operation. The 0.25mm undersize specification indicates this bearing is intended for crankshafts that have been machined to this dimension, allowing for the restoration of proper clearances. GLYCO is known for its commitment to quality and precision, making this a dependable choice for engine repairs. Proper installation of main bearings is crucial for engine longevity. This GLYCO bearing is crafted to facilitate correct seating and function, helping to minimize friction and wear within the engine block.