tune time
I would take it to the track again and get some seat time and notebook, run it several times. Vary your launch technique ( deep vs shallow stage), reaction times, have a buddy record your launches in front of and behind your car and compare your reaction ( while you're are watching the video of when you should have took off). This is sorta off subject but since you put in a new torque converter see what it does, real data , not just "putting you back in your seat". Work on the tune first, you have great parts in your combo, trans brake ..... in your near future.