i have a h22a head lying around in my garage and im trying to figure out if it is usdm or jdm. how do i tell the difference from a jdm h22a head from a usdm h22a1 head? are they both coded as p13 on the front of the head? its says P13 with HF-1 on the front and on the end of the camshaft covers by the distributor and the vtec solenoid, it says P13 - 1. does that mean that i have a usdm h22a1 head then?

 

I'm not sure how you tell, but there isn't a difference.