I have a 2002 F350 CCSB with 5.4 gas V8 6-spd manual and 4x4. Truck came new with overloads, but no sway bar. Truck would lean terrible bad with no load... Installed Helwig sway bar, Rancho RS 9000's and stable loads before I even bought my TC. I weigh in at 10,960 on average. As low as 10,600, but a high of 11,600. I used it as it was with the stock 16's, till I ran across a used set of 19.5 visions with 265-70 load range G's. Later after adding a superhitch for towing with. A 32" extension I added air bags, but just to level a bit. Usually 10 psi or less, just enough to disengage the stable loads, then I let out enough to just engage the stable loads. Everything rides very nice! I have been all over Alaska with this rig, and the two best additions were the 19.5's and the Helwig swaybar. The sway bar and Ranchos do well at controlling sway, but the 19.5s really stiffen up the ride where it feels very solid and comfortable,
Since you have the 250, I would highly recommend finding the overloads and frame pads from a 350, and bolt them up and install stable loads. Then add the Helwig, and upgrade the shocks. Mount camper and weigh. Decide if 19.5's and or airbags are needed.
If you have the auto in your 99, you may want to make sure it has an extra cooler, as heat kills those transmissions. I have two 2000 Excursions, and when towing , keep a close eye on trans temps...
Good luck!
Garry in AK
