I have a 65 mustang with a 408w that makes 670hp with a C-4 and a 4.30 gear. I am getting ready to put about 250hp of Nitrous to it what would be a good gear. I race 1/8 mile and 1/4 mile tracks. Also will I loose on my 60ft times when changing another gear? I am trying to keep my RPM down to 7500 at the end of the 1/4 mile.