First I have the 350 Vortec and it is running pig rich. Need further help please.

1) How do one know if it is running in Limp Home Mode (LHM)?
2) Had 65 pph injectors, changed to 61 pph injectors, Fuel Pressure 12-14 psi still runs rich
3) Much AC noise on Knock Sensor wire. Can Knock be turned of in TunerPro. Also will try 1 Kohm resistor on wire to ground.
4) Can 74 pph 7.4L injectors be used by raising fuel pressure?
5) Is 74 pph injector tighter, then increase fuel pressure to it yields higher fuel flow?
6) If changing to 74 pph injectors, what fuel pressure as a start should be used?
7) Should I use external fuel pressure regulator referenced to manifold vacuum?