Here's a photo of the rear of the Blitz gauge. If your gauge is like this
one, you'll need to snip off those mounting studs as short as
possible.
You'll need to make a hole in the cluster case for the boost line and the
lighting power connector.
I started by taking a Dremel tool and cutting away all of the ribs and
bosses in the area where the gauge would be mounted. It was fairly easy,
but use caution as the plastic melts fairly quickly:
Once the material was removed, I dry-fitted the gauge to
see how close the fit was:
Dry fitting helped me to determine where I needed to drill holes in the
back to accommodate the connections. Once I had the fit correct, I
centered the gauge in the opening and used a few dabs of hot glue to
secure it.
Here's a shot of the back of the housing, showing where the holes need
to be cut to permit the boost hose and electrical connector to attach:
I had to cut through one of the traces to make the lower hole large enough. I
then soldered a jumper cable to one side of the trace and used a ring connector
to install it on the other side. The red wire below illustrates this jumper:
Next, I had to provide power for the gauge lighting. I chose to tap into
the power circuit to the main gauge cluster lighting, seen below by the
yellow and black wires: