My days in manufacturing, a long time ago, we spec'd a 64 finish on high speed turbine and generator shafts. These ranged from 6 inches up to 24 inch diameter shafts. The turbines were operating at 3000 to 6000 rpm while the gear driven generators operate at 1500, 1800, 3000 or 3600 rpm, depending on the frequency of the country of destination. The bearings in these applications were not round but eliptical (wide at the horizontal joint, allowing for an oil wedge and the climbing factor of the shaft (hydrodynamic wedge) - the shaft would rise and rotate about 10-15 degrees from the vertical centerline of the bearing shell. The oil film was based on a rule of thumb bearing to clearance of .0015/in of diameter, the shaft climbing at rotational speeds and the flow in GPM at 25psig.

Then, to complicate this even more, throw in a rotated tilting pad bearing and try to make some sense out of that feed and drain system - I tried including talking to the designer.

How does that translate to automotive technology? You still have clearances to worry about, pressure and flow and a hydrodynamic wedge - look at the direction of the feed holes in the crankshaft to determine where the wedge is formed. This provides the semi metered flow to the babbited bearings, and provides the cushion for wear resistance. This flow can be disrupted by heavy scratches or it can introduce early wear to the bearings. If the measured fit, by micrometers is correct, and there are no significant scratches, i.e. feel by dragging your fingernail across the journal, there should be no problem. But you also need a good finish in the 64 range as well. Pur it together and run it!!!!