The F-Series, Silverado and Ram numbers are deceiving especially the F-Series. They do this for bragging rights of sales numbers.
Ford F-Series isn't a model vehicle, it is a 2 models that make up 5 class of trucks. These include F150 all the way up to F550. The F150 is the only truck of the F-Series that is really considered passenger vehicle. The F150 is also on a totally different chassis than F250 on up. The F250 and F350 are it's own class as they share everything the same such as frame and body and only differs by components such as brakes, suspension etc... that separates it by GVW. The F450 and F550 are chassis cab trucks with the exception of one specialty loner F450 crewcab built for passenger for bragging purposes.
Silverado and Ram also does by including multiple class of trucks into one. They share the same cab but differ by chassis. Like ford, they include 1/2tons up to chassis cab models.
So if you really break it down by models. Ford F-Series includes F150-F550. Silverado includes 1500-3500 and Ram includes 1500-3500.