Oh my.

The 7.3 Powerstroke only was available until 2003 before Ford switched over to the 6.0 and then the 6.4 in 2007. Therefore, that truck either has a 6.4 in it and you swapped in a 7.3 (which would be ridiculous), or you started with an F-350 between 1999 and 2003, swapped the front clip, mirrors and bed, and re-badged it. Looks like a nice rig though.

You know what they say about people who have big trucks...