Final Update: I found a NOS alt, with proper 77mm pulley, from SS Member and vendor Hill Billy Wizard (Thanks John). Installed it on the truck, no more alt 2 light, at idle, no pulsing of light, it seems to have fixed the problem and is NOS alt as described.
Now, back to original problem with previously purchased iso-ground alt 2: John was also kind enough to send me an extra 77mm pulley, at no charge, with my new purchase of the NOS alt. (Double Thanks to John) After installing the new 77mm pulley, on the previously purchased new isolated ground alt, the pulsing of the alt 2 light stopped, so it was indeed the over-charge, using the smaller 66mm pulley, that was causing the alt 2 light to do the random dance when driving the truck. (Thanks Warthog, for the 77mm pulley info).
Now back to the original alt 2, that caused the problem, after purchasing a new 27si kit, from asp, I had it rebuilt and it too is now back in action, the regulator was weak and was causing the alt 2 light, at idle, to be dimly lit, even though it was putting out proper voltage, it was just getting tired. So, I have (2) back-up alts; the old original that has been re-built and the on-line purchase iso-ground unit that I added the 77mm pulley onto.
I installed the NOS unit from H.B.W. onto the truck as the permanent alt.
So, in closing, the alt 2 issues have been repaired, I have 3 new belts and I have (2) back-up units in reserve. Also, based on all the swapping I have done, over the past couple of weeks, I can swap an alt out in 15 minutes.
If you don't want to run the risk of buying an iso-ground unit, on-line, without proper pulley size or worry that it will truly be an is-ground unit, Hill Billy Wizard has 77mm pulleys and NOS alts. Suggest you reach out to him.
Thanks to all those that have helped me solve the problems, without the collective knowledge of the SS family, I would have been chasing this for who knows how long. Thread Resolved!