smoke, they are about 8" apart. One, the coolest, is drilled in the round flat spot(this is on ATS man. )just ahead of the expansion joint, this probe is verticle, the hotest reading is just above the turbo, towards the rear where 5 & 6 dump into the turbo, this one is horizontal. There was as much as 150* difference bet. the 2, and when we switched the guages and probes, they read the same difference. So the difference is where the probes are located, not in the guages. I hope thats clear.
Larry