Fuel Pressure woes

Replaced my stock fuel pump with a 255lph (high pressure) Walbro a couple weekends back and bought a fuel pressure guage (not the in dash type).

I measured my fuel pressure after the swap and it was rocking at 32psi at idle (18 hg vacuum). I thought it might be the fuel pressure regulator and swapped one out today from a Merkur(one of my three FPR's).

I played with the car a bit and found that if I take off the vacuum line to the FPR the pressure goes up to 40 psi. It stays there if I keep the manifold port plugged but the vaccum on the car goes to 14hg.

Does anybody have ideas here

Thanks Eric. I kind of freaked out there, thought something was wrong.

I read sometime back on one of these forums, can't remember which or what site, that it should be 40 psi at idle.

I took my hood off wired the guage where the passenger could read it and went for a cruise.

At 0psi manifold the fuel pressure reads 40psi. At 15psi manifold the fuel pressure reads 55psi. That seemed normal to me according to the +1psi boost/+1psi fuel rule of thumb.