the (RUST) is minimal, youll have ZERO problems, but as I stated previously you should, contact the piston manufacturer, and ring manufacturers, for info on where and how to measure the pistons and what the correct bore clearance, and hone grit should be! as fit and lubrication is critical to durability, get the fit too tight and you can scuff the pistons, the engine tends to run hotter. get the piston to bore side clearance, too loose and the engine burns oil and may be noisy and slightly more prone to detonation if you get oil past the rings, pistons are not exactly round, they expand as they heat up so you must know where to measure clearance