I've got a Fuel Pressure gauge that Lee Thompson sold me. Its mounted "UNDER" the rear edge of the hood but the gauge is external so you are looking right at it. It does not touch your hood's paint or the trim at the rear edge. Its got a stainless line and a special 84/85 fuel rail that has an AN fitting to hook the gauge to. This, IMO, is the only way to go as you can see what your fuel pressure is at all times. Knowing what it is at idle doesn't tell you what it is on boost. An example, you set it at 35psi at idle but your pump is not able to keep up and at 18 lbs of boost you "should" have 53psi but instead its down at 45 and you getting knock. Better to know than guess. IMO, of course.
I'd sell the gauge, stainless line, and fuel rail for 150 plus shipping. The gauge really looks nice on the car also. Its got the "anodized" blue on the holder and the gauge is polished with a white face. Its liqued filled and 3", I think.
Anyone interested in it give me an email and I'll email you a picture of it.
Also got an 84/85 throttle body that has been opened up as far as possible (about 59.5) Lee told me how to do it and it really helps the hot air cars performance.
Regards,
Bob