The newer supercharged Harley trucks run 3.73 gears. They would probably wake your truck up. What is your opinion on the Kenne Bell blower. I would like to add a supercharger to mine and was thinking of the Kenne Bell. If you would like to see what a real dog is you could trade yours for my stock 2000. I might even be able to throw in a couple bucks for your trouble. Hahaha. But seriously, my stock 2000 will break the tires loose from a dead stop and it is equiped with 3.55 gears. Not smoke them, but you know that they are spinning.
It has been my experience over the years that if you don't want to do a brake torque and get the 20" beasts spinning then you would be better off spending a few bucks on a higher stall torque convertor before changing out the rear end gears. The secret is to get the rpm's up high enough to make the power and the rest is history. I have a 2003 100th Anniversary HD (sweet) with 3.73 gears and a 2800 stall convertor from http://www.rpmoutlet.com/lighttorque.htm
This combo allows the motor to get right into the 400+ ft/lb torque range and it's quite the show I must say. Putting a 4lb lower crank pulley on the motor to raise boost to 12-13 lbs combined with a good tune from SCT or equivalent really wakes up the potential. The torque convertor is not cheap but it really improves the lower end performance. With the increased boost now coming in about 500rpm lower now, the torque band is much wider as well and comes on a lot sooner too.
I find now the truck is so responsive that I have to really watch how I leave the stop light. Too much pedal = too much attention. And I live in a small town where there is only one truck like this and they know where I live. So you get my drift. 20" rubber gets expensive too, but they keep making new tires just for that reason I guess. You only live once in this world. Enjoy it.