Wizard,
I am not a motor home owner or have any RV experience to speak of however, I store lots of them with my storage business.
What I heard a few years ago is:
the 454 will out pull the Fords on hills but the Chevys have a wimpy chassis and dont handle well with that big box on em. They weebole-wobble down the road.
I have one veteran RV guy who bought a new RV on a Chevy chassis and after his first trip turned it in for a Ford chassis. The thing was all over the road. This guy has had lots of RV's but never a new one and went for the Chevy.
One thing that this guy pointed out about the Chevy chassis is that they dont sit level. The rear is jacked up to carry the weight. If ya look at one, you will see what I am talking about. Also, if you look at the steering gears, they are (or were) right out of a pick-up truck. The Fords have a bigger gear in em.
This is what I was told a few years ago. It could be that things have changed?
I drive a Dodge and have a BBC in my boat and really dont have any bias twards Chevy of Ford. I do agree diesel is the way to go. Personally, I would find a sweet used diesel pusher before I bought a brand new gas job.
Be good, Jim