Well I aquired the car needing head gaskets about a year ago. Haven't had a chance till now to get it apart and running. I pulled the motor last week and when i went to pull the heads I noticed that the exhaust cams were retarded a bit and the intake cams were advanced a bit. What i am trying to determine is if this was done on purpose or it was an accident when someone changed the timing chains or something? I may need to have the heads decked a few thousandths to make sure they are flat and not warped so valve clearance and timing is a concern since i dont know a lot about the n* yet. Is it common to change the cam timing in these motors in that manner, and what are the ramifications tuning wise to doing this?