What gear for 6K in 1/4 mile?

My 360 with 230@50 .488 cam ran out of umph at about 5500 and best E/T was shifting at 5K. Changed from 4.30 to 3.91 and went from a 27.3" tire to a 29 and picked up about .4 when all was said and done! Car laid down at about 1000' with the 4.30's and pulled all the way through with the 3.91 and taller tire.