This listing is for a set of (8) +.010" Under Size Journal King Engine Connecting Rod Bearings and a set of Main Bearings compatible replacements for SBC CHEVY 305 327 350 383 engines with 2.100" Large Journal Size.This set is for Crankshafts which have been turned .010" under size Journals. Alecular material is used exclusively by King. It is an alloy of aluminum, tin, copper and several other elements. Because it is an alloy, it maintains its properties throughout its entire depth, delivering consistent and reliable performance. Available in your choice of under sizes! Just click the box of your particular under size needed to order.