i got a d15z1 head and the guy that had it before me tried to put a zex cam in it and messed with all the valves and it diddnt work so he gave it to me now i put stock cam back in and its all messed up now considering that the head only moves like half of the valves when u turn it how do i adjust the rest? someone told me that the head has to be turned at like 2500 rpms before the other valves move so i dont really know thx for any help.