The boost gauge uses an existing (plugged) hole in the Cummins engine block. You just have to remove the plug, reduce the size down to what's needed for the vaccuum line, run the line to the cab, and wire up the gauge.

The one problem with this basically easy installation is that this seems to be a rather turbulent area of the engine intake. As a result, at high boost, the needle will shiver, rather than giving you a nice solid flat reading.

Pictures coming...