Before I rebuilt me QSX, I did a bunch of searching.  I bought my OH kit from Highway and Heavy Parts.  They have some videos on YouTube.  The best one I found is a guy that goes by Rawze and has a 16 or 17 series of videos on YouTube.  He shows rebuilding an ISX in frame on a truck.  Some of the QSX have timing gears called scissor gears.  They are a pair spring loaded gears, mounted one in front of the other.  The purpose is to keep pressure against their mating gear to eliminate the back lash.  I bought the specialty tools to overhaul my QSX and sent them to Coastalbend to use, when he overhauled his engine last year.