SuperSprings SSA13 Helper Springs 11-26 GM | 99-07 Ford | 11-16 Ford W/O Overload Spring. Fits: 1999 - 2003 Ford 7.3L Powerstroke; 2003 - 2007 Ford 6.0L Powerstroke; 2011 - 2016 Chevy/GMC 6.6L LML Duramax; 2011 - 2016 Ford 6.7L Powerstroke; 2017 - 2019 Chevy/GMC 6.6L L5P Duramax; 2020 - 2025 Chevy/GMC 6.6L L5P Duramax.