New Old Stock Turner Pistons Number 520 for a Champion Hot Rod. These are partially machined with the knob on top removed, the double ring groove machined and the locator pin installed. The diameter measure at mid point of the piston is 2.514" so they can be machined to whatever size you want.  These are in excelent shape but on piston looks to have gotten damp at some point in its shelf life so there are discoloration visible on the skirt.  The wrist pin hole is 0.81" on both no retainer groove machined. Tops need polishing. Shiping in USPS Medium Flat Rate Priority Box.