If you want bottom end torque to launch a heavy truck, bigger is not always better. Engine AND drivetrain parts have to work together to make things happen, and usually larger immprovements on one end call for equally large improvements on the other.
Torque is the "twist" or rotational movement that gets things moving. Bigger cams and t/bs, fancy intakes all increase torque, but do it at a higher rpm range. So the drive train needs modding as well with lower gears and maybe high stall Torque Convertors. Thes mods get you engine into its peak torque range quicker with a resulting boost in acceleration.
I believe that most novice "modders" mistake horsepower for torque. While the two are interrelated, they are also completely different. Torque is what gets you moving, horsepower keeps you there.
If you want to get 6000 lbs of Dodge ram moving from a dead stop, especially one with bigger tires and bigger lift, you need bigger gears and other torque enhancers, not top end boosters like big tbs and cams.
The problem is that engine mods are cheaper, easier to install, and are cooler visually. There's nothing to show off about gears or a high stall converter. And these items aren't cheap, create heat, and bleed off horsepower, which top end is, providing you regularly travel well over the legal speed limit.