Well he is the deal, I am going to put a t56 in my 7 soon but I wanted to go to the track and see what it could do with the auto, it also has a b and m quick shift on it. I was getting decent 60' times and okay reaction time but in between the gears weather or not a just left it in drive or if i shifter manually it free revs and hits the rev limiter. I was taking my foot off the gas when i would shift and tryingto let it catch but if i went to hit the gas again it would bounce of the limiter again. My friend used to have have the same shift kit in hid monte carlo and it would grab very hard. The tranny might just be bad but if anybody thinks it is something different let me know. By the way my best run was a 13.5 because of this.

 

tq converter .....

 

If it's a 4l60e are you sure everything is hooked up right like the VSS?
Try searching camaroz28.com lots of good info.
If you can get that tranny shifting good you should have no problem hitting a 12.xx
I ran a 12.66 in a mostly stock LT1 auto setup, first and only time at the track.