Which 1 Ton SRW Diesel Truck Has Highest Payload???

A Gasser can give the truck a bigger GVWR based payload but in the real world less than 100 lb difference based on the trucks RAWR payload which is how much load we can carry in the bed.

The OP is looking at GVWR based payloads in trucks on dealers lots and may or may not indicative what he can actually order or what is actually out here on the road or other dealers lots.