F-53 Chassis Air Bag Questions

[Farmhills53565]

So I keep learning about our 1999 Holiday Rambler Vacationer 32 CG built on the F-53 chassis. I knew going in the suspension was going to need some upgrades. The rear end hangs a little low so I bought an Air Lift AL57410 Air Lift LoadLifter 5000 Air Helper Springs for the rear and went to install them today. They are supposed to fit the F-53 chassis. I don’t know what it is called but there is a an area below the floor but above a sheet metal pan where they run piping, duct work, and other stuff I assume. The seam for this sticks down below the top level of the frame rail and is in the way to install the upper bracket. I worked in a body shop years ago so I am able to cut out the piece I would need to and re-flash and seal it. All that said has anyone here run into this? Would the firestone air bags fit differently? I went with the air lift because they are suppose to have a bump stop inside them that the firestones don’t have. I have one other question. Under the OEM leaf springs there are two blocks. Is this OEM or did some add this trying raise the back of the coach?

[CA_Traveler]

Have you considered replacing the 22 year old springs?

[dodge_guy]

Each manuf and/or model has a different build style. Some are flat floor, others are like yours. Nots sure how the Firestones fit? May be worth a try? Or get some side by side install picks to help.

[MountainAir05]

MY 99 the firestone bolted right on, my unit was 38foot. But you never know what the manufactory did when they bolt/weld the body on.

My firestone mount to the rail did not line up to the pre drill holes so had to drill new holes. My floor was flat. Newmar body.