It was a while back, my memory isn't too clear on it, but it was lifter durability so we were trying to fail a solid roller lifter (which is pretty difficult). It had some pretty aggressive cam lobes and if I remember correctly the springs were a slightly stiffer than needed (trying to stress the lifters as much as possible). Simulated circle track laps I believe, probably 4,000 to 8,000 rpm and back over and over. Usually for durability like that we try to push it right to the limits of whatever valvetrain combo we're running. So maybe some slight float/bouncing but controlled for the most part.
