An E450 is chassis overkill for a 24 foot Class C.
However, chassis overkill is exactly what we wanted when we shopped for a new 24 footer. Our E450 is carrying around 11,800 lbs., so it never overheats with full air conditioning on at any outside temperature and on any grade, climbs any hill easily (4:56 rear differential ratio), brakes smoothly and confidently under all conditions, and is very stable on curves and in cross-winds because of it's rear track being wider than an E350's. We load it up with no concern for any negative affects because it's always way under-loaded. The E450's frame steel is thicker than that of the E350, so platform stiffness is improved for less stress on the coach structure if used occasionally off-pavement, too.
I couldn't imagine driving a vehicle around that is constantly loaded as close to it's max capacity as is the case with most small Class C motorhomes on only the E350 chassis.
Of course one can get away with the E350, but IMHO it's only adequate ... but not the best. There's reasons that certain Class C manufacturers like Lazy Daze build only on the E450 chassis - including their smallest models.
2005 E450 Itasca 24V Class C