I got the Stack Pro gauges fitted at a local garage, its deffo 1/8npt which was the same as the stack gauge sensor
The garage were really good with me and mentioned that it made a change to do something different, i think the starter motor ended up having to come off to gain access to the sensor, they maybe played it safe as they did mention that they didn’t want to damage the thread in the block which would have give bigger problems......
I ended up going for the flashy
Stack Pro gauges, i.e the Boost gauge is set to illuminate green off boost, red on boost, and flashes on over boost, Oil pressure gauge flashes at low oil pressure and is set to flash at high oil pressure, i.e. when the oil is cold, to many revs the gauge will flash red until the pressure drops with the warm oil (engine at correct oil temp to put my foot down), Hope that makes sense
I think the rest of the car mad family here are a bit jealous of the gauges
they do look good
Ill try and post a video of them working when i get it back from Chris at EFI parts
as its currently away for a brain transplant
Hope the above makes sense, as i end up getting the advice what to do with the car from my car mad family & then they leave me to explain things on here which isnt easy
Sandra