I disagree with there being enough area for a plain bearing if you only replace the roller element. Roller bearings have different load carrying capacity than a plain bearing for a given width. The plain bearing relies on a fluid film to be maintained and the area of that film determines the load. I'm not on top of the math behind it but from working with machinery I guarantee you that if you have a 1" wide roller or ball bearing, you will need at least a 2" or more wide plain bearing to replace it. Bearing surface velocity and other load factors affect it too. The bearing width on a stock 273 rocker is what, 1 1/4 - 1 1/2" wide and they still wear the shafts out over time with stock springs. Bottom line is I would not rely on a 1/4" wide plain bearing on either end of a rocker to live a long time in a high performance motor.
