It kind of studders a bit when fully boosting, like it is hesitating. I didn't have this problem before I removed the head but since I haven't set my ignition timing yet, I was figuring that was the culprit. I also need to check my vacuum hoses because my idle is a bit high and my BOV doesn't open fully under full boost even though it is adjusted to as loose as it gets (I am running 8 psi and it shouldn't be that loose).