I got into this a little late didn't read all the post's. Myself my motto is KISS= keep it simple stupid. I always look at myself first. First thing I see is launch RPM. I raced for years foot braking and found that you need that full shot of fuel on the launch. Be consistent on your rpm, Meaning, don't leave at 2700 one time then 3300 the next. I ran a holley and would leave at 2000 rpm to get the full excellerator pump shot. Made a huge difference if I changed. I hope it is something simple for you. Its usually cheaper.