Make sure that you get a coolant water filter on it as soon as possible. Also change the coolant if at all dirty. You will plug the first coolant filter in about 400 miles, and the second one in about 2,000 miles. The third one should last a year or so, around 15,000+ miles. But change it every year.
Coolant filter Napa #FIL 4070 and a kit to install it is napa #FIL 4019. I put a coolant filter on my 97 Bounder with a 460" gas engine. So far, no need to change the water pump, or any coolant problems. It keeps the inside of the radiator pretty clean. Heat transfer is better, no minerals in the water pump to mess up the gaskets or pump seal.
I installed one on my class C with 1/2" ball valves at the inlet and outlet, so changing the filter is very fast, with little coolant loss.
The biggest problem with the 6L is the oil cooler can get clogged when there is junk in the coolant. Then there is lack of coolant flow to the engine exhaust cooler (that exhaust gas is sent into the intake manifold in a effort to cool the spark temperature, thus making less Nitrogen Oxides). When the exhaust gas cooler is overheated (due to loss of coolant flow thought the oil cooler then the EGR cooler) the exhaust gas cooler overheats and cracks, letting pressurized coolant to flow into the intake manifold and engine. Coolant does not compress, and typically will punch a hole into the piston instead.
International recalled all of it's trucks and school busses, installed a coolant filter, and fixed the problem. Ford did not fix the problem.
Your SRW F-350 only has a 9,900 GVWR due to the tiny tires (3042 pounds weight rating each) and has a very limited cargo rating. The 2003 F-350 SRW had the same 9,900 GVWR, while the dually has 12,000 (give or take a few pounds). While not nearly as much as the 2005 and later trucks, it is better than what you have. But a much better pick would have been a 2005 and later dually, with 13,500 or 14,000 GVWR. No need for the air bags on the newer truck.
Good luck,
Fred.