I currently run 3.91. I also have a 4.30 pumpkin. If your big block is putting out good tourqe you do not need a lot of gear. With a good tourqe converter 2800 or so, 2.94 and or 3.23 are great gears. I ran a 14.65 @ 96mph with 2.94, 11 inch converter. The 3.91 gears just get me down the track quicker 14.018 @ 95mph.