Typically on stock Ford FE blocks, the upper main bearing holes don’t perfectly align with the upper bearing oil holes. This occurs at main locations one, two and four.
To improve main bearing oil flow, you can chamfer the saddle holes slightly to blend the saddle holes to the bearing hole.
Alternatively, you can slightly blend the holes in the bearing or do a combination of the two.
Removing a small bit of material in the bearing shell isn’t a big concern (as long as you don’t get too carried away), since the upper bearings don’t experience the loads that the lower bearings face.
Blending the oil holes will improve oil feed to these main locations, especially for a performance-oriented build.