I agree with starting at 6lbs and working from there. I spent a lot of runs figuring tire pressure for my altered. All in all, I ended back at 6 lbs. In fact, I staggered air pressure at one time. 6.0 on left and 6.5 on right. I hear its not uncommon depending on tire roll out and launch charicteristics. Its really a trial an error event to see what the car likes.