It may depend on the years. All I know is that when I put a 1986 MIJ neck on an 2011 MIM body (and vice versa), the heel of MIJ neck was a tiny bit rounder and the pocket of the MIJ body a fraction longer. The holes matched up no problem, but there were little gaps in the corners of the neck pocket with MIM neck on the MIJ body. The middle of the heel was touching the body, but not the corners.
With the MIJ neck on the MIM body, there was a tiny gap between the entire heel and the body. Again, the holes matched up, but the MIJ neck pocket was slightly longer.
Quite honestly, it didn't impact the tone or sustain at all, but it bugged me all the same and switched them back.
MIJ and MIMs from around the same period may be a better match, but I wouldn't assume so without further advice.
Last edited by CPplaysBASS : 01-30-2014 at 02:29 PM.