There's a reason why they're down there, that's the best place for them. You're trying to create a 4 link in the rear using the leaf spring as the upper links and the most effective place for the other link is a long ways away from the leaf. so the best place for them is under the axle tube. You can run the bars on top of the ubolt plate but they have to be a good ways from the spring to be most effective and it can be hard to do that in the space required.
If you want to use the single ladder bar it's a little less complicated but not much. You still need to match the spring geometry but you have a little leeway because of putting a shackle on the end of the ladder bar. You also have to be aware of the torque effects on the vehicle when you're climbing, it may not be what you want in some cases.
A single torque arm on the top of the diff generally doesn't work too well because it's too close to the leaves to work right.
Making the world better, one truck at a time.
SW-ORD
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