I don't think I'd be using Oilite bushings for rocker arms or anything in a car engine. They are designed for use where there is scant oil supply like electrical motor bearings and other light duty applications, and are a honeycomb structure that retains oil. I don't think they will support the load pressure that a true bearing bronze will either. For any bushing/bearing in a car engine I would be using 660 bronze or 952. That's whats used in punch press crank bearings and it can take a beating. The oil film is what should be taking the load anyway, so making sure the rocker is getting enough oil to the right place is where the effort should be made.
