Industrial Injection GM Remanufactured Heads For 2004.5-2005 LLY 6.6L Duramax - PDM-LLYSHThe Industrial Injection LLY Duramax Stock Remanufactured Heads are designed to be a factory replacement. Complete ready to bolt on. Heads are first jet washed in a high pressure spray cabinet to remove oil and dirt, then glass beaded to remove carbon. Next they are checked by magnafluxing, (cast iron only) or pressure testing. They are visually inspected for defects that would make them unusable. New High Strength Alloy, Heat Treated iron based valve