Traction,traction,traction... you should try a set of drag radials and see if it helps. Drag racings real key is getting it to hook up. Doesn't matter if you've got 800HP if you can't hook. I'm guessing your losing traction even if you can't see/feel it. I modded my car similiar to yours along the way and that was my problem. So,I added upper & lowers,drag shocks/struts and drag radials and brought my 60 down to 2 flat. I'm sure you know this but make sure your traction control & overdrive are off. If you do some of the traction upgrades you should be in the 13.7 range. Don't let your E.T. bother you hell we've all been through the same problems. You MOD your a$$ off and then see lil or no results.:wallbash: Then one day it all comes together and you smile from ear to ear.
Heres some things to think about no two days are the same,temp/bp,wind,clouds,sun,lane choice,track prep,tire pressure,fuel,etc. all figure into our magic #'s. I keep a log of all my runs so I can compare them you might find that helpfull when tuning for bracket racing. Good Luck!