1930 Studebaker Main Bearing Question

[richard m]

On my 1930 Dictator 6, I have a question about the third main bearing (the flanged one that carries the crankshaft thrust).  My machinist friend has noted that the bronze-backed bearing shell half that sits in the block does not sit flush with the block.  With the shell fully seated in the block there is a gap of .025" on both ends of the shell.  In other words the shell is .025" shy of being flush with the machined surface of the block.  Is this something Studebaker did on these engines to facilitate oiling of the thrust surfaces?  All the other 3 main bearing shells when inserted come up flush with the block surface. So the third thrust bearing is unique in this regard.  Of note is that this third bearing is the only bearing in the engine that did not have oiling grooves cut into the babbitt on the face that crank turns in.  When I disassembled the engine, there were no shims behind the bearings or other added parts besides the shells and caps.  Any sage advice out there?  Thx, Richard