The 1979 Dodge Class C I had, had a Van nose, factory 440/727 and a Dana 70 with 4.88 gears. I know for 100% certain that it had a full frame under it with 1 ton or larger suspension. It was 24' long, and could not have survived had it been a unibody. That's not to say that there wasn't a remnant of the B van front frame rails under there.....but they did not carry any weight of the vehicle. The thing had a full frame from front to rear. I sold it to another Moparts member back around 2009-2010. Not trying to be argumentative, but I spent plenty of time underneath that thing on my back working on maintenance to know what was under there.