I remember back in 1976 (I was 18 then) my dad bought a new Chevy van, our first van for a family vehicle. The car it replaced was a 1967 Plymouth Fury-I. The rear end of the car had severe sagging issues on vacations so my dad wanted assurance never to have such issues again, so he bought a Chevy van equivalent to a 2500 today.
That van shook and rattled through every mile until he replaced it 11 years later with a 1987 Ford Econoline van, equivalent to an E150 today. My mom and dad were extremely pleased with the smoother ride, and it never had sagging issues either.
In my parent's case, they learned a hard lesson in over-kill with vans. I suppose that is why I feel the way I do about a Phoenix Cruiser 2350 built on an E450 chassis. Motor homes are houses on wheels with an earthquake going on with every mile. There is a difference in a 7.0 and an 8.0 quake.
I do need to mention that our 2007 PC-2350 has a little rear end sag when on trips, but it isn't significant. I attribute it to the position of our fresh water tank placed directly over the rear bumper. We could travel with less water but like having a full tank for roadside showers and such. Newer model years relocates the tank to a better position. I think the newer chassis with the greater load rating would sag less or not at all. That would be a good question to ask PC owners with newer PC2350s.
