No, a standard piston for a 4" bore should be good. The piston will actually be a bit smaller of course than your bore (which is what YR is asking for), that is what determines your clearance. Mostly when buying pistons only the bore diameter is given, but the piston usually is bore minus clearance.
With your little wear even a slightly oversized piston would be too big and require boring or honing on cnc equipment. That is why YR states to just dingle berry hone it (which is honing with an electric drill and, err, the dingle berry hone).
Anybody feel free to correct me.
