You can't look up JDM Honda part numbers in the US, that I know of. The only time I have ever seen JDM D15B part numbers is when some guy in Japan working for Honda hooked up his friend with the info and his friend posted them for people. However, this was for the JDM D15B VTEC, which I am pretty sure is going to be a different block from the non-VTEC version.

If you want to try, here is the thread with D15B VTEC part numbers. However, I do not stand by them at all because I am fairly certain that it is going to be different from the non-VTEC D15B. I've done a lot of research on the D15B, and while there are tons of unknowns about these engines, it is extremely unlikely that they have the same block parts.

The best thing for you to do is measure, as you asked in your first post. Also, look on the pistons and such in your D15B and look for any markings indicating part numbers, in case some might cross-reference with USDM part numbers.