2004 Mack AC 427, Truck Tractor, Heads, Fits to: Mack CH613, (Used) 2003 Mack AC HEAD, Serial Number: 3M1831, CID: 728, For more information about this item, give us a call. We ship Worldwide! (CRG HEAVY TRUCK PARTS) 929 W PULASKI HWY ELKTON, MD 21921, Serial# 3M1831, Casting# 3M1831, Truck Year 2004 1M1AA18YX4N156170