This is a general overview showing the common ways that I mount gauges. I mounted my SPA digital gauge in the overhead console. I wanted something different and inconspicuous. My truck has the deluxe overhead console with the block off plate. I offset it to the side to allow the addition of another gauge in the future. The console drops down by removing a single screw at the front. All wires were of adequate length, and tucked easily above the head liner, and run behind the A pillar. I placed the signal box for the pyrometer so that I could access through the side dash fuse panel access door. I have since relocated the menu switch (red button shown) to inside the remote garage door opener panel. This same installation can be done with analog gauges. The gauges can also be mounted on the A pillar with a gauge mounting pod.
Pyrometer probe location
The pyrometer thermocouple can be mounted in the passengers side manifold by drilling and tapping to 1/8″ or 1/4″ N.P.T depending on the type used. While it is best to remove the manifold to do this, many have been drilling and tapping the manifold while on the vehicle by running the engine to blow out the chips as they are made. I pre drill the hole at 3/16”, and follow with a step drill to the appropriate size. The step drill (use dry) has a single, wide relief that lets the chips blow out very well. Be sure to wear eye protection! If one were to remove the manifold, the gaskets are reusable, and you could also install the N.P.T. fitting, and grind away any protrusion to eliminate any obstruction to flow prior to reinstalling. The depth should be adjusted to the middle of the flow path if adjustable.
Boost Tap Locations
I prefer, whenever possible to plumb the boost gauge to a solid part of the engine. On the LB7 models (except 2001), the casting that feeds the intake (from the intercooler) and houses the boost sensor and intake heater is long enough to provide a simple installation. I drill and tap to 1/8” NPT. To do this, I remove the intercooler hose and insert a shop vac hose to draw out any chips as they are produced. It is also not a bad idea to change the oil shortly after doing this. The alternative is to cut and tee into the wastegate hose. This is a simpler operation, but does not provide a firm mount.
On the LLY engine, I remove the upper intake casting and drill/tap as shown in the accompanying pics. One shows the manifold off of the truck, and the other installed. Installation is the same whether mounting a transducer (as on the LB7 setup above) or a pressure tube as shown in the LLY pics.
Drill size recommendations can vary from mfr. to mfr. so check for markings on the tap. Typically, 11/32” is appropriate for 1/8” NPT, and 7/16” is appropriate for ¼” NPT