CLose call V belt ruined

I did make another discovery. The alt. was actually attched to a differnt screw hole. Meaning It used to be attached to the far screw hole, I had engine rebuilt, and when they reinstalled for whatever reason (actually cause they stripped it) they used the closer hole to mount it. I dont figure that would make any difference in the alignment or the way it sits, right?

Since putting the old belt back on, and not having it be so tight, it seems to work. But I still see it vibrating at certain RPMs.