A+ main bearings can be identified by the center locating tab in the main bearing cap. 1.75" main bearing diameter in standard aluminum material. Order by size from drop-down. For performance applications, we suggest converting the block to accept VPM733 Vandervell VP2 bearing with offset tab. Some sizes are now available only from aftermarket manufacturers, but all are quality products. Ref: BHM1573, AEM3427.