Bert, I dont think there is any reason to "cross brace" the factory upper or lower links. they do not see any side to side load nor should they ever. You leaf springs take thins now and you woud need a pan hard bar to keep doing it.
Watch out for factory air ride. Most put the panhard on top of the axle. If you stick your head under the truck you will see that unless you go up this *could* be a room issue.
Some factory air ride does not use a pan hard bar, like airliner by freightliner. but this suspension is intended for little or no articulation because high way trucks need the stability. I know the airliner is plenty heav duty, our last heavy haul truck had it with NO panhard bars and we would run 70-80,000 pounds on it when we pick up the two tag axles on the quad group and turn sharp off raod on job sites. This truck also sucked as soon as you got off the road. The suspension would not let both tires have even weight, if you ran over a hump the axle would basicly go strait up and take the other wheel off the ground.
Now, our new Kenworth has Newway and full rear lockers. Even with OUT the lockers locked it will go many more places off road. The newway suspension lets things articulate. it is used in many on/off road trucks, lots of it up in canada in logging trucks. Same with Mack cammel back suspension, it may not be air but it gives articulation, thats why macks work well off road compared to a freightliner with air liner suspension.
SO what I am saying is watch out for some "factory" air ride. You may find your self stuck on a curb if you dont have enough weight to force it to flex. Also keep in mind if you get too much "flexy" suspension it will suck for sway and need sway bars. PERSONALY I am going to look hard for a light duty Newway or just start from scratch and make my own.
My stock deuce suspension works well at 70 MPH....
