What's the max weight of loads for dry van?

I know the trucks and trailers that Combined Transport had for their glass division were setup especially for max weight and we could easily turn 48.5k. But that's flatbed too, but with all the equipment on it those trailers were a bit heavy (had glass racks, tarps, and all other associated hardware, plus a set of lumber tarps, chains, etc for general commodity loads.)

I'd be really interested to see just the engine weight difference between say, a 12.7L Cummins and a 16L CAT. Or between a 9 speed and an 18 speed.