I googled "Honda PR3-4" and within the first 4 results, I found this answer...
"PR3 is the casting code for the B16A/ITR head. B16A are PR3-4 ITR PR3-3."
The lesson here is to FIRST do research, such as using Google, when you have a question. Gather information and if you dont conclude on a clear answer, then it makes sense to post a detailed question.
