I have a 309 first gear in my 4.10 geared Roadrunner with a 28 inch tire. (275/60R15) and let me just say it's too much gear. It's a quick shift. Use 355 gears or a tall tire. This is with a 450 hp 440.
I have 4.10s but also have 30" tires so it will help. I like the slr for the street/na even if it is a bit much for the nitrous, the car is going to be a compromise.