I had a 2001 LB7 and ran it for ~ 50K miles. That engine would flat get it. I didn't realize it until I traded it off for a 2002 crew cab. That (2002) particular LB7 was weaker and nothing but an injector destroyer.
I ditched it for a 2007 and the LBZ is turned up a bit (HP) but I havent driven it much since I bought it new in July 2007.