(GOOD USED/ RUN TESTED/ FULLY INSPECTED) 2004 Mack AC Diesel Engine (EPA04) EGR MODEL, Engine Family 4MKXH11.9H70, 427HP, 11GBA : 23978YP1, Engine Serial #: 4J1751 visit JJREBUILDERS website for more information or call 786-377-5210 REF STOCK # 005974