A 4.30 or even a 4.10 would be my choice for what you are doing. Your hp comes in very low I would bet? My main reason for being on the conservative side is all the torque you have and keeping the car hooked up on the launch. It will also keep the rpms down in the traps saving the life of the parts quite a bit. I run a 4.56 and a 33.6 tall tire going 150 mph, and cross at about 7300. A 4.30 would probably work as well as the 5.46 gears in my car.