[cobalt327]

Originally Posted by 95chevy406

Well my local parts store has them for over and undersize main bearings

As said earlier you want 0.010" undersize bearings. The package will often have -10 as a suffix, or just 10.



The individual bearing shells are also marked for size. The King bearing below is a 0.010" undersize bearing:



There are 0.001" and 0.002" oversized bearings, sometimes used to selective fit bearings to journals for a closer tolerance. These are called X and XX bearings, respectively. I'm not aware of over the counter oversized bearings for a SBC that would be 0.010".