2004 Mack Aset AI400, Engine Assys, (GOOD USED & TEST RUN & INTERNALLY INSPECTED) 2004 Mack AI Diesel Engine For Sale, AI, 400HP MAX, Fits 2004 2005 2006, Exhaust Family # EM, EC, TC, CAC, DI, SPL,1EGR, 6 Cylinders, 11.9L, Turbocharged, Engine Serial# 4C0503, Stock# 7119