that one i dont remember its beeen a lonnnggg time. Order upa 12-450 and see how that one works out then you can go from there. Might as well get a list going here.
id order a 12-400 to see where it sits. summitracing.com you can return the ones you dont need they refund you fully even if used. 12-400 try it out if its to high then drop down to a 10 inch spring. I wouldnt start dropping spring rates cause you need the higher spring rates for the heavy ass on these trucks.