If your having trouble with your coach riding level or wheels duels are rubbing on wheel well roof when coach leans to either side you may correct it by installing air-bags.
Another way would be to go to a good leaf spring company and they can add leaf springs to all four corners.
Had two Fords that could not carry the Newmar coach's placed on them. First coach the box was uneven on the chassis and adding leaf springs different sizes front and back, leveled coach so it ran level down the road and made driving a completely new experience.
The second coach was heavier and the passenger side, which is the heavier side, rear duels would chafe the wheel well roof. Had a lean to that side also.
I installed AIR-LIFT air bags over the four corners with a compressor and air control valves with a gage for rear wheels up at the dash area. The control gage for front bags was installed in same compartment with compressor and control valves.
Air would have to be added manually to add or release air from bags. They now have automatic level controls to keep air you desire in bags or keep coach box level.
Cost back in 98-2000 was about the same for both upgrades $1200. The shop did the springs and I installed the bags because dealer said they couldn't install bags because the brackets could not be installed at rear wheels. They were wrong.
This may give you some idea what you will be running into. Drilling through chassis frames is work and I didn't take wheels off made a pattern to drill holes from other sides of mounted wheels.
I liked having more control of chassis with air because the change in weight as fuel decreased and holding tanks weights changing could be corrected. The ride was somewhat quieter and smoother.
You still had a truck chassis back than but its all we really had until the Workhorse came out.
If I was younger and had some money I would look into the
NEW F-53 chassis by Ford. Saw it at the Tampa RV show and was impressed. Its beefier and has Bilsteins, heavier springs and the Ford V-10 engine with a much improved transmission and Ford now calls it a designed MOTOR HOME chassis with a booklet that says it. They also said they will keep the gas engine and give Workhorse a run for their money.
Think they have been looking in on the Workhorse forum here on irv2 because they have corrected everything that WH missed when they first came out shocks, toque bars,air intake and such.