I have a Magnafuel 500 pump, -12 feed, -10 to the front into a magnafuel log, 2 holley regulators on top for nos systems, -8 out of the log to a magnafuel regulator, split out of that regualtor in 2 -6 lines to a single carb.... Problem is I cant get fuel pressure low enough... Ill get it close then it creeps up and pegs the gauge... I read on yellow bullet to adjust the bypass (-8) I adjusted it, and still the same... also read to drill the bypass fitting to 3/8, tried that with no luck... also read that I might try a soft spring or cutting two coils off the bypass spring, tried that and its better but still cant get the Holley or magnafuel regulators below 14lbs... anyone else had this problem????

12 volt system with a Alternator, wired with a single 12V relay...

Where are you taking the reading from(under hood)
and is it a liquid filled gauge(but they usually show
lower as the heat gets to them)... also is the pressure
climbing while the car is running

Yes I have the same problem, put in light spring in it and drilled out bypass. I have almost the same setup -12 to pump,-10 to log,-6 to tHe carb and nitrous with holley(pro systems) regs. Mine will still do it on a rare occasian.

I would install the Magnafuel regulator in between the pump and the log with the Holley regs after the log Is the pressure opening the needles and seats when it creeps up over 12 lbs? If not maybe the gauge is inaccurate I had one new Holley regulator that would not hold the pressure, it would slowly creep up and blow the needles and seats open I replaced that one (it had a tiny flaw, scratch, across the seat) with another new one and that solved the problem. Let us know what you find

Yeh cab, its pushing past the needle and seats... also I thought of putting the regualtor before the log, but it cant hold back the pressure either...