I have a jdm b16a, i know the "factory tuned" is around 160-170hp. I believe the b16 from like the usdm del sol is around 130hp (not really important). My question is what makes that hp difference? Is it mainly the cams and valve train? Could i swap my jdm b16a valve train (or whatever makes the difference) into a usdm b16 head and keep the same performance? would it be a direct swap over? Thanks very much.