Fuel pressure guage
I ran a mechanical fuel pressure gauge on the cowl on my last car. I made an L-shaped backing plate that I could slip between the slots in the cowl and mounted the gauge to that. I did it this way so I could hold the backing plate with a pliers and screw the gauge mount to it, isolating the gauge mount with rubber to keep it from tearing up the cowl.
If you run a mechanical inside the passenger compartment, you really should run an isolator like
this. Regardless of how good the line is, I wouldn't want to have a fuel line inside the passenger compartment.
This time around, I was planning on using Holley's electric gauge, which seemed pretty cheap compared to Autometer and comes with a sending unit. It's part number
26-503 and I think both Summit and Jeg's carry it.