I ran into the same issue with my G63B head. Cam journals were pretty badly worn but I think I had managed to bring it back into service myself. This is the break down of the method I used to remove the cam play in this post - it's not a step by step description with pics (I should've made the effort but I was so annoyed with the condition of the cam journals I just went straight into it) http://www.mightyram50.net/vbulletin/showthread.php/2566-Intake-manifold-porting-question?p=32110&viewfull=1#post32110