Interesting info on F250/F350 rear axles. UPDATE 01 24 14

Since my 250 diesel had the camper package with overload springs, the only difference from same era 350 was the wheels and 4" axle block instead of my 2".

Things are changing. Look at the new Ram 3500 SRW verses 2500 and you will see bigger differences. However, I still feel the manufacturers could eliminate one SRW model and still meet the needs of all their customers by offering different GVWR packages.