Originally Posted by 92TypeR

PR3 is the head ID #. The folowing number, either 1 - 4, is from what casting it came from. I've seen ITR heads have every number, 1 - 4, and many different b16 years have different #'s following the ID #...example, my b17a head was PR3-2, my '92 JDM Xsi B16 head is PR3-1, my '00 JDM ITR head is PR3-4, my '97 USDM ITR head is PR3-1.

...There is no way to tell from the ID # and casting # which model/year/make the head came from. The only sure fire way to determine if the head is actually an ITR head is the green paint behind the distributor, which is the paint they slab on there in the factory when they select the best looking ones to go out for machining, and the minor portwork on the intake ports, and larger intake valves.

Originally Posted by 92TypeR

YOU CAN NOT TELL IF A HEAD IS AN ITR HEAD BY SIMPLY USING THE CASTING NUMBER OR DATE CASTED AS A REFERENCE!!!!

Sorry for the yelling, but it has been explained numerous times now

Originally Posted by sheekdude

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hooch’n &raquo;</TD></TR><TR><TD CLASS="quote">PR3-2 JDM B16
PR3-4 USDM C5 and USDM B16A2</TD></TR></TABLE>

This is actually true since i have all three sitting here right now. Both of the pr3-4 heads one is from an em1 00 civic si and the other is from a dealer bought 01 itr head and they are exactly the same casting. The only way i could tell the difference was by checking inside the intake valve chamber and there you have it. The si one was rough and coarse and the itr one was smooth as a baby's bottom at least 2-3 inches up.

Hope this helps.