The newer VORTEC engines may be more tempermental than you think. Remember, that's a cast iron block, and can come with aluminum heads and/or intake. These metals have 2 different rates of expansion when heated or over-heated. My 2000 CK3500 with just 176k miles+ has the 7.4L Vortec, and has had its intake gaskets replaced twice already withing 20k miles.
The factory vortec heads are iron. Intake problems aside as the intake was plastic and aluminum on the 5.7 and 7.4
