I think there might be an N47 head from a Maxima that guys are using which has a smaller cumbustion chamber. This would of course give you a higher compression. If its an N47 head off another Z, the N42 is most definetly better. I'm a die hard N42 fan on NA motors. You have all the same design charactaristics as the earlier E88, but with larger valves, and harder seats.