I have gt40 p heads with a gt40 intake roller rockers, comp cams chromoly pushrods, tfs springs and a n-41 cam with twin turbos and im making great power with the combo, also changed out all the bearings to clevites while i was in there, i dont know what the power is but the car pulls on new camaros all day every day i would guess easily 450 though on 10lbs of boost