What is the difference in a 379 and 389 Peterbilt?

The 379 Peterbilt was last made in 2007 and was replaced by the 389 thereafter. Among many design changes were a longer hood ( the longest hood offered to date), and wrap around style headlights. The first 389's went into production in late 2006 as "2008" models and officially replaced the 379's in March of 2007. The "Transformers" movie featured the character "Optimus Prime" and portrayed that character as a 379 Peterbilt.|||basically the overall design