[blykins]

We do the bronze bushings sometimes when the lifters are really tall. Under high lift with high spring pressure, the lifters will want to "wiggle". One, it's easier to R&R a bronze bushing. Once cast iron is oblonged, then the only choice is to....well....put a bronze bushing in it. Another reason is that we can leave the bushing sticking up out of the lifter bore some, so that gives added stability at full lift.