Well I have never seen that on a gear unless the gear was moving. Question 1 is that an adjustable gear or solid? If its solid make sure the bolts aren't too long in the holes and bottoming out allowing the gear to move. As far as the rev kit I like them personally and have run them in all my motors with roller cams. Yes it keeps the roller seated on the cam and in the case of valve train failure (pushrod, lifter etc.) it keeps the lifter from beating the cam to death.