Stainless, Bushed PRW Rocker Arms

The bolt holes in the heads for oil flow through #2 & 4 pedestals are enlarged for oil flow around the bolt or stud, whatever is being used.
The problem is poor quality bronze &/or incorrectly alloyed bronze, not lubrication. Bronze is a porous metal that is designed to run on minimal lubrication because it stores oil in it's pores. Two examples jump out where there is no continuous oil supply & the bronze survives for 000s of miles. Upper bush in the dist shaft & bronze valve guides; especially exh valve guides with positive valve seals. Subject to tremendous heat, plus any oil that manages to get past the seal gets pushed back up the guide by positive pressure of the outgoing gas.