Up to 150 mph at the stripe, you should be fine, about 7400 rpm. That is figuring on decent lockup of the converter. You might want to call the converter builder and ask them . I suspect though that you will be told to try it. More gear with the glide will help, so if you have faith your motor can trap as high as 7600, i would run the 4.56. what track are you going to run at? I may be in your area right now.