Roller cam idle RPM

The crossover tube does help at high rpm but it also doesn't restrict oil to the lifters, you can still run hydralic lifters with it . Witch you can't do with the bushings and tubes. So in my thinking there is more oil to the lifters and a better shot at getting more splash oil to the rollers, just my thinking though. I have run rollers on the street with 550 to 600 pounds over the nose and luckly I have not hurt a roller yet ( broke a link bar once at the track that hurt!).