It would be wise to check the area under the pivot ball as the camshaft being used could be forcing the slot in the rocker to or past the limit of travel thereby locking up the rocker arm on the stud. Look for marks on the stud itself and take necessary action. High lift cams require longer slots (some standard arms are available with longer slots). Inspect the ends of the slots that the rocker pivits on and consider roller rockers as free horsepower because of less friction. At a bare minimum find the fractured pieces as Bob stated above, they will lock up an
oil pump in a split second! Look amoung the coils of the other springs as well as in the pan. Do not run it again until you are satisfied that you found the pieces.
Rick..........