I didn't read your entire post, but if the motor felt like it just stopped for a split second it could be a fuel problem. I had this same problem first of the year. My motor at about 180' would act like somebody cut it off then right back on. My fuel pickup lines were in the front of the tank and It was getting air in the fuel lines when I launched.
Make sure you're not loosing fuel pressure when going down the track before you make any changes.