Alternator discharging battery?

Ok so got my car running and the alternator all hooked up its a 3g into a 84 svo with a 92 5.0 in it

so i went to check voltage running and voltage sitting

got like 12.6 while it was sitting and when running it was 12.5

so whats going on here did i do something wrong? I only had to hook up 1wire from the external regulator that was on it to the wiring harness i got from rjm injections, the old external regulator is no longer in the vehicle

even when revving the motor to 3000 rpm it was still running a lower voltage then when the car was not running

Ok i may have found my problem, somone should really add a diagram to the useful tech threads section since i think maybe the 1984 external regulated 2g to 3g upgrade is a lil different, i did alot of searching and found that i may have possibly missed a wire i was supposed to run to the alternator

this is from rjminjection page

Alternator Connections for Other Years:

On your 84 external voltage regulator, you have the following:
F, S, A, I

Unplug the wiring harness going into the external voltage regulator. Either splice into with your new wire or make a blade connector that will go into the old wiring harness. You will need to tap into two of those wires:
The F will not be used.
The S will go directly to the I on the 3G. The A will go directly to the A on the 3G. The I will not be used.

Looking at it from the 3G viewpoint:

The BAT goes to the inline fuse.
The stator connector goes to the S connector on the 3G.
The A connector goes to the A wire on the old wiring harness.
The S connector goes to the stator connector on the back of the 3G.
The I connector goes to the S wire on the old wiring harness.

its to dark and ****ty to go outside n look right now ill check it tommorow, but this says differently then the bronco diagram everyone whores around, think possibly i just received bad information

i only hooked up the S wire that comes from regulator harness to the I wire on the 3g, ill look into it tommorow