2008-2010 Powerstroke 6.4L Mahle Set of 8 Pistons w/ Rings - .50MM - Reduced Compression (224-3953WR-.050)2008 2010 Powerstroke 6. 4L Mahle Set of 8 Pistons w Rings . 50MM Reduced Compression (224 3953WR . 050) The MAHLE 224 3953WR . 050 Piston With Rings (Standard Reduced Compression) are the perfect way to reduce compression iSn your 2008 2010 Ford 6. 4L Powerstroke or Navistar Maxx Force 7. These MAHLE Pistons feature coated skirts and are manufactured to the specifications of your OE pistons but with a reduced compression height.