Safe guess on the 3500 SRW would be at or near the 9900 of the F350 equivalent. A GVWR of 10,001 puts you in vehicle class 3 and is legally a medium duty truck. GVWR between 8501 and 10,000 is class 2 with medium duty emissions. GVWR 6001-8500 is class 2 with light-duty emissions.