Undersize Bearing Usage Guide: Notes

WARNING: This page is about a different car, the 2005 Nissan 350Z. However, it is still accessible from the selected car via links, so may be relevant.

When the specified main bearing oil clearance is not obtained with standard size main bearings, use underside (US) bearing.
When using undersize (US) bearing, measure the main bearing inner diameter with bearing installed, and grind main journal so that the main bearing oil clearance satisfies the standard.
CAUTION: In grinding crankshaft main journal to use undersize bearings, keep the fillet R [1.5 mm (0.059 in)].

Fig 1: Crankshaft Main Journal
Courtesy of NISSAN MOTOR CO., U.S.A.