alternator or power sterring pump

[boogiedown27]

Hay guys,
on my 78 cutlass I have a new problem that started to surface..last week I wrote about the gen. light coming on sometimes and I was directed to the alternator may be going bad. Well now I noticed at night when I have the heat, radio and lights on..the car will start making the awful high pitch squeal when I push on the accelerator..If I cut the lights off it will not do that? I was under the impression that okay the power steering pump is causing that? but in the daytime all is fine, I still have not necessarily got the right bracket that would of connected to the removed air compressor, but the power steering pump does not have that second bracket for support (yet)...since I have headers the bracket tht I got from the salvage yards looks like a close fit, so I was going to go and survey again before I try to remove the headers..As far as the alternator goes I noticed that ever since the emmsions guy touched the back of the alternator with a screwdriver it sparked..and now when I drive at night it will make that loud squealing noise only when I accelreate and low type chirp at idle...the belt tension is tight, and the power steering belt is almost as tight? So any suggestions?? Ijust don't wanna go spending $$ and It doesn't reslove the problem?
Thanks