sportsman's advice
Trans rebuild & a converter before you go out--no sense bustin' stuff up first, then having to repair it. Then I'd go for perhaps a rear gear change, 3:91 or 3:54---no sense going crazy for so races. Assuming the rest of the car is mechanically sound, I'd consider nitrous, but keep in mind that also means some ignition tweaks & better fuel delivery (aka more $$$$) so you may not want to do that.
Other than that, if you can figure out how to remove weight particularly from the front, that's essentaill free horsepower so you shouldn't have any problems.....