The Trucks with GVWR over 14K are cab and chassis class 4 and 5 trucks.
Just to provide a little background regarding the F450 pickups, the 2008-2010 models had a GVWR of 14500, which made it (just barely) a class 4.
This is just my opinion, but I think there was some concern on the part of the Ford medium duty truck brand that the F450 pickup was “stealing” sales from the medium duty line. Consequently, the 2011-2013 or 2014 F450 pickups were dumbed down, rebadged F350’s. Then in about 2015 Ford went back to very much the same chassis as the ‘08-‘10 trucks, but the GVWR was lowered to 14k, and there it has stayed.
Prior to my current 2016 I owned a 2010 F450 pickup, and I’m telling you there is no reason the 2015-16 F450’s couldn’t have also had a GVWR of at least 14,500.
:):)