fuel pressure regulator setting

[high perf mopar]

i have an aeromotive #13205 pressure regulator,with there pressure gauge, thats plumbed into a dead head system,3/8" lines,mallory comp 110 at the tank.1 filter before the pump,1 after the regulator.

set pressure motor off,5 1/2 lbs,been this way  for awhile,maintains that setting for awhile but,today while retuning the motor after some upgrades/changes,the pressure dropped to 3.8?and stayed there?no flucuation that i could see.

after cooling down back to 5 1/2 lbs???instructions that came with it says to set while motor's running,,wont it blow past the shutoff seat upon cold start if i do this...   
 

[cudabob496]

your basic Holley needs 6 psi to 7.5 to work, and I suspect getting seat leakage would require
8 or 9 psi at least, but just a guess.

Those little tiny gauges in the engine compartment on the fuel systems can be really inaccurate.
I trust the 2 and 5/8 electric autometer on my dash much more!

[Chryco Psycho]

I stay below 6 with carbs , at WOT the float may not have enoiugh fuel in the bowl to hold the valve closed & could flood above 6psi , at low rpm generally this is not a problem , even with lower pressure as long as the volume is consistant you will not have an issue