My buddy just put a 98 d16y8 head on a 99 d16y7 bottom end. The y7 is out of a DX and this swap went into a 98 civic SI. He says he can hardly get this thing to rev out to 4000. Is there something else he's gotta do besides just swappin the head? Any info would be appreciated or if someone could point me in the right direction.

 

does he have any check engine light?