International Engine Succession
| 1980-90 | 1988-95 | 1993-04 | |||
| 6.9A To 59208 S/N | S/N 500001 Up | S/N 000500 Up | |||
| 6.9B 59209 Up |
| Up to 1993 | 1993-1997 | 1993-99 HEUI | 2000-2003 | 2004-9/14/06 | |
| S/N To 618496 | S/N To 980819 |
New Generation S/N 2U980820 1194038 |
S/N 2U1194039- 2000001 |
The 6.9L and 7.3 can be identified by the engine number stamped on the front top left side of the engine. The first three digits indicate the engine displacement, The fourth indicated natural or turbo charged. The fifth and sixth indicate the use (M2 indicated truck use). The seventh indicated what country is was built in (u = USA the remaining digits are the engine serial number.
7.3LT/444dE can be identified by the serial number on the lower rear left side of the engine crank case, right of the lube oil filter head..