"It's worth discussing the fact that the rocker tip is actually quite busy across the valve-stem tip. Even with proper pushrod length, the rocker tip starts from the inboard side of the rocker. As lift begins, the rocker tip moves toward the center of the valve tip, approaching the middle of the valve at approximately half of maximum valve lift. As lift continues, the rocker tip moves past the valve tip's center toward the outboard edge of the valve stem at max lift. Then as the valve begins to close, the rocker tip retraces its movement back to where it began. In essence, the rocker tip sweeps across the valve-stem tip and then returns. This is what the rocker tip does with proper pushrod length. With either too-short or too-long pushrods, the roller tip starts in the wrong position and travels much farther. This can lead to all kinds of dangerous situations, all of which can also create valvetrain problems."
Install on one of the front rockers and watch the rocker tip as you rotate the motor.