How big a tire are you running now? I'm running ladder bars and leaf springs with floaters and am running 14x31 Goodyears with the spring relocation kit with stock frame rails and mini tubs. I have a friend with the identical set-up(suspension and tires) and he has run a best of 9.30 @ 145mph... with a Jericho 4-speed. The ladder bars were a big help.