Carb Choice

Congrats on a serious torque monster. Considering 3.55's and 27" tires, i agree with the others...vac. Will take some trial and error tuning, but when it's right, you'll love it.
With that said, if your converter choice happens to stall in the 3000/3500 range you could probably use a DP. Doubt you'll need a converter that loose with the cam you're using and the 4" arm.