The Class 3's are about 14K lb GVWR, Class 4 at 16K lb GVWR, and Class 5 at 19K lb GVWR. The F450 pickup was really a F350HD last few years but is coming back to its roots in the new models.
The reason I am looking Class 5's is that these triple slide TC's when loaded will approach 6000 lbs, I plan on at least 1000 lbs in additional batteries, towing heavy on a long extension may add another 1000 lbs, plus I may add additional water and fuel tanks later. This is getting too close to the capacities of the Class 4's.
