just to give you an idea of what a stock AOD'd modded stang will do...
There was a guy in a 91 GT AOD (completely stock tranny) with TFS heads, E303, GT40 intake and 3.73's at the track i was at last saturday. He was running about the same that I was that day which was mid to low 13's on BFG drag radials.
You really need to get a good converter and valve body or trash that AOD and throw a T-5 in there.
Its not that expensive at all to do if you do the work yourself.
I did it for a whopping ~$200 (after selling the AOD)
With a brand new T-5, you're probably looking at about $1300 minus some cash if you can sell your AOD (dont blow it up if you decide to go this route!
)