This listing is for (8) .020" Under Size. King Engine connecting rod bearings and a set of main bearings compatible replacements for FORD 289 - 302 ENGINES. 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. Your choice of under sizes. Just click the under size box needed to order and place in Cart.