I would think a loaded 4000-6000 lb trailer would be maxing out a 55 1/2 ton's pulling ability. And don't expect to keep up with traffic either. 4 drum brakes, a short wheelbase truck, and an overloaded trailer spell out disaster. A heavy poorly loaded trailer can quickly take control of the tow vehicle.
I would not even consider towing a trailer with 4 wheel drum brakes. I would also reccomend towing with a longer wheelbase than 114". In the situation listed above, I believe this 55 year old 1/2 ton is not enough truck.
