In Scott's case, it was just cycle life of the rocker. There were hours of running with high spring load. They break between the adjuster and the oil grooves on the ID when they break. I have seen bad bearings sporadically when I ran Super Stock hot and heavy. Not hard to put new bearings in them, but it usually kills the shaft unless you catch it before it goes long. I think the resonance in the bearing could shorten the life of the rocker body. The ones Scott broke had bearings. I changed him over to bushings when we went to the steel rocker bodies. A good oil film on a bushing, on a nice slick shaft won't give up any power to the bearings in a running engine. It might feel a little better turning over with a wrench, but bearings won't make more power, and bushings won't fail as long as oil is present and adequate. A needle bearing is designed for rotation, not reciprocation, which loads the same area all the time, and let's the unloaded rollers "chatter"......like the fat lady singing with the wine glass. Something somewhere is not going to like that frequency at some part of the range. Bushings are the way to go in my opinion.
