Adding Bronze Bushings to Ductile Iron Rockers

It has been quite a few years since I ran W2 heads, so the memory has faded since then. But as far as I can remember from having both a set of bushed and non bushed rockers, there were no differences between them other then the bushing. The part of the rockers the shaft went through were a lot thicker and beefier on the W2's then the 273 adjustable rockers.