I a 2000 model year GM casting has survived this long - assuming it has some thousands of miles on it - it'll likely be OK for the foreseeable future. All of the AM General block casting date codes are 5 digits in length. Navistar cast all of AMG's 6.5L blocks and heads. Visit the following forum thread to learn more about casting date codes and some other good stuff.

http://www.thedieselpageforums.com/t...ad.php?t=24325