Just saw in your other thread your Av had a 8.1. If that's the case you will not be happy at all with a 6.0. The small block needs too many RPM's to have any pulling power at speed. Pay the extra go diesel.

6.0L sucks.... Don't buy a tow rig unless it has a Diesel motor. This is the time of the year you can buy them cheap. 09 2500HD crew cab's loaded are going for around $35K.