I have a 2019 SuperDuty Diesel (Dually). I don't know that 4 inches would matter that much, especially if you have automatic levelers.
I would be far more concerned about how it might affect the ability to hold the pin weight. We have a giant 44' 20K GVWR fifth wheel. The pin weight is somewhere between 4K and 5K lbs, can't remember exactly. I wouldn't want to be messing with my suspension in any way than the factory intended.... while needing to pull my home down the road.
2018 Grand Design 399TH (44') • 2109 Ford F-350 Dually
With 2016 Harley Heritage • 2013 Sportster with a sidecar!