2004 GM 4.3L guinea pig

I have been using my 04 Blazer 2dr 2wd 4.3L to practice tuning with HP tuners. Since I started I went from a 18.1 to a 16.2 in the 1/4 mile not bad for a butt Dino and not knowing what I'm really doing sometimes. The 4.3L is stock except for K&N cold air intake.

Chevrolet Blazer Ls 4.3L bracket racing solo pass.
https://youtu.be/deo5oLdJ9hA

Last race for bracket racing and I believe this guy sandbag me. He taps his brakes right at the 1/4 mile marker. I am a stock 4.3 l 16.7 in the 1/4 Mile there was no need for that just to win.
It was 108? and track temperature was about 151? Update found an old video of the Nova with his dial in time at 12.1 so when he raced me he changed it to 13.7 when he raced me.:mad:

https://youtu.be/-k3mO2dWPYQ