904 for drag racing

I have a 68' Dart that weighs 3100 lbs. I am using the original 904 tranny. I race the car on weekends and drive the car to local shows. This tranny is behind a pretty stout 273 cu. in. engine. The car runs 12.60's and this tranny works great. All I did was rebuild the tranny, put a low gear set in, manual valve body, and an 8" Turbo Action 4800 stall converter. The car launches unbelivable and to my surprise is very streetable. The car turns 1.67 60 foots.
Hope this helps.