2008-2010 Ford 6.4L Powerstroke Valve Covers work to shield your valve springs and rockers from being contaminated with dust and debris, while keeping any engine oil from leaking into components that could be damaged by that. As you make more modifications to your F250 or F350, having these valve covers becomes so much more important as these issues tend to be more prevalent and frequent. For more intensive applications of your Ford 6.4L Powerstroke, make sure to upgrade to stronger and more capable valve covers found at Alligator Performance. Ford Powerstroke Fitments: 2008, 2009, and 2010 Ford 6.4L Powerstroke.Submodel Fitments: XL, XLT, Lariat, FX4, FX2, Limited, King Ranch, Platinum, Tremor.Some exceptions apply, please see individual product pages for specific fitments.