Didn't mean to cause an argument here and maybe came off strong but all 25/35 series pickups are essentially the same chassis for each mfg and a completely different chassi than the 15 series trucks.
GM and Ram for sure have the same frame, brakes, axles, wheels etc. I suspect the same for Ford too.
Fundamental difference between a 35 and 25 series regardless of mfr is rear spring capacity and gvw based on springs and legal class weight limits.
Vinsil is right that there are now more options mostly Ram for engine power ratings, transmission availability and rear suspension design but the back bone and most of the guts are the same 25 to 35 series.