Manley Size (STD) Stroke (79mm) Bore (99.50mm Grade B) SINGLE Piston w/ Rings WRX STI EJ257 2004-2021

Part #: 612000CB - 1. Manley Subaru pistons are crafted from high - strength 2618 material. They're designed for easy DROP - IN installation and match OEM Grade Range A or B bore sizes. Just pick the right grade range pistons for your engine block. Each grade range has the proper clearance built - in. These pistons come with Premium Chrome Moly 0.180' wall pins, perfect for moderate boost. Included are Total Seal piston rings. The top ring has an AP steel configuration, and the second ring has a Napier profile for great oil control. For high - boost engines, we highly recommend installing 9310 alloy 0.210' wall wrist pins (part no. 42546).

Using these Manley pistons is easy. First, make sure you select the right grade range of pistons according to your engine block's needs. Then, perform a DROP - IN installation. When using in a moderate - boost engine, the standard Premium Chrome Moly 0.180' wall pins will work well. But if you have a high - boost engine, switch to the 9310 alloy 0.210' wall wrist pins (part no. 42546). As for maintenance, regularly check the piston rings for wear. If the oil control seems off, it might be time to replace the rings. Keep the pistons clean to ensure long - lasting performance.