what the correct procedure to do this??
I heard somwhere about disconnecting a vacuum line, but I'm not sure if so and which one??

also, should there be fuel pressure with just the key on, and if so, what's the specs???

 

You have to disconnect and plug the vac line going to the fuel pressure regulator. Then the pressure at the rail should be 43PSI plus or minus 3 or so PSI with the engine idling. No reliable procedure for checking it with just the key on since battery voltaes can differ a little bit.

 

The fuel pressure should be stable and not jump up and down. When I first checked mine and had a bad pressure regulator, the needle would jump back and forth between 30 and 60 insanely fast. Fixed the regulator and left the vac line hooked up, I ran 45psi, while the gauge is still hooked up I reach over and revved the engine, pressure should jump around 2500 to 3000 rpm, if that happens you're in the good. As a note, if you install a Walbro 255lph pump, there's no real need for an adjustable regulator unless you want to reduce the fuel pressure, it will put you right around 50psi when the vaccum's off.