I have my existing block wall in my basement and existing drywall I added furring strips and put drywall on block part.

Wayne,
I can't quite visualize what you are talking about, but I think you are saying that you have two planes of drywall, and one plane of drywall is an inch or two proud of the adjacent plane of drywall.

If that is the case, you have two choices: you can either install a vertical piece of trim at the seam between the two planes (and live with the face that the two areas of drywall are not co-planar), or you can install shims (that is, more furring strips) on the sunken plane and install a new layer of drywall so that the new drywall is co-planar with the other surface you are trying to match.