Gauge Installation on a Gen 2 Dodge Cummins

Lay the gauge mount over the factory pillar (or new factory pillar w/o speaker hole) and mark locations (notice X's) for the wires/tubing to pass through.  Mark your locations low in the gauge hole so that the wires/tubing do not have to bend upward.  Use a step drill and drill your holes large enough to allow the connectors to pass.  The step drill is recommended as it will not crack the plastic.
Now is a good time to make sure that your gauges will fit in the pod holes in the mount.  If they're too tight simply use a piece of 220 grit sandpaper and gently remove some material from the inside of the holes.  Only sand a little at a time and check periodically.  You do not want to open the holes up too much.  You will be press fitting the gauges into the holes so you want them to fit snug.