Get a 12' Spartan body single rear wheel van, you'll be alot better off,and comfortable! MPG around 12-14 in a Spartan with a 5.4 gasser in it.
That's all the GVW a 1 ton chevy is?Are you sure that wasn't a 3/4 ton?That seems awful low on the GVW for a 1 ton, being as how my Ford is 9,600#, and the new Fords are 9,900GVW at Telegraph Ford, Spartan body, 12 ft.
The Payload rating of a 2011 Express 1 ton extended is 3200 lbs. Not sure how much of that would be gobbled up by the added weight of the van body.
The Chev looks to be 9600GVW for the G3500 extended.. Probably closer to the 9900 for the short wheel base.
There should be no difference in the Gross Vehicle Weight Rating (GVWR) between the long and short wheelbase Chevrolet vans. Payload rating yes, because the short wheelbase weighs less.