If your referring to the grade 8 bolts,why are they an issue?Different heads have diffrent depths maimly at the corners,some need a 3-1/2 bolt or stud to get full thread engagment.Full thread contact is important for clamping loads and less chance of breaking or pulling the aluminium threads on aftermarket heads.The studs or bolts provided with the rockers are sometimes too short and need to be substituted and proper length studs are not always available.