Pistons designed for 'long rod' (6") A series motors. These are race pistons custom made. Bore size is 2.821, Compression height of 1.250, pin diameter .812", flat top with valve relief. Top ring is 1.2mm height, second is 1.5mm and oil ring is 3.0mm. The weight of each piston is 202 grams or .45 pounds. Pistons sold as a set of 4 with rings and pins included.