Fuel pressure - what should it be?

[427cobra]

I have an aftermarket EFI system that uses a Ford EEC4 control unit from a 1989-1993 mustang gt. It has a Mallory adjustable fuel pressure regulator and is a return type fuel system. The regulator has vacuum connection that raises or lowers fuel pressure 1:1 with manifold vacuum/pressure. Engine has 36 lb/hr injectors in it. With the vacuum line disconnected, what should the fuel pressure be set at? The fuel pump only runs for a few seconds when the key is turned on, so I pull the vacuum line to check the pressure. I believe this is a correct way to set the pressure.

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[socalwrench]

I'm looking into the same thing- what the correct fuel pressure is for the eec 4 5.0L.

Is the aftermarket rising rate fuel regulator necessary? I thought that if it's regulated to the specified pressure- the injectors would operate correctly. I mean, it's the EEC that is adjusting the injectors movement electronically, not by changing the pressure (mechanically).

Apparently, the factory FPR is adjusted by engine vacuum also.