See the first post from the OP. His pedal feel ok. If you have never run these GM Calipers, the first thing you notice when they are out of adjustment is you get excessive pedal travel.....this is not the case. Granted, they may need adjustment but this is not the root of the problem.

He has the wrong combination M/C to Calipers. Simple fix.

I also run these aluminum rear Wilwood Metric Calipers in place of the Stock GM calipers. Much better for track use and competition.
http://www.summitracing.com/parts/WIL-120-7197/