Why does my Dart hate a 2 step ???

I recently installed a 2 step box for the Tbrake on my Dart .I tried it last Saturday at the track and the Dart hated it.Every time i would launch it would bog ,then clear up and go.I tried pills from 3200 -4000 and everytime it was the same thing.I ended up putting a 7000 pill in it so it wouldnt hit and the bog was gone and it ran better 60 foots instantly ,duh go figure.It seemed to me that it was loading up with gas while it was on the rev limiter ,but im not sure.Please bare with me as i am new to Automatics in Drag cars ,as i have always ran 4 spds in the past.I would like to use the 2 step for the convenience of it ,but dont know what i should do to fix the problem .Here is a vid to look at of my first run ,so you can see and hear what im talking about .Thanks for your imput ...


[ame="http://www.youtube.com/watch?v=ELN86EauBAc"]YouTube- Dodge Dart bogs to a 7.29 1/8 mile pass[/ame]