While installing a set of Hitachi carburetors on my engine i discovered this part had a small hole and needs attention. What is the part number and where can i order it?

This is the part! Where can i get it?

That looks like the Anti-Backfire valve p/n 14835-25601 per the online catalog, used on the L24 and L26 engines. It is NLA from Nissan, probably not a BD or MSA item. Your best bet will be to get one off a salvage car or someone who has pulled all emissions equipment but is holding on to the parts.

Try your local parts store. I just checked O'reilly's and they have a part that looks like your part. It's called an emission check valve...I do not know what parts places you have in Panama however.

Amazon.com: Standard Motor Products AV7 Check Valve: Automotive