Before this big, bad pickup arrived, manufacturers largely used upgraded versions of their light-duty trucks to handle heavy-duty work. The 1999 Super Duty was a separate model line with its own style and hardware underneath.
You can run a conventional oil 5K miles but you should be able to run a synthetic oil 7500 to 10000 miles. Royal Purple API-licensed synthetic engine oils allow motorists to travel as many as 12,000 miles as the recommended oil change interval.
That will help your engine get the full benefit of synthetic oil.) Vehicles in which 0w-20 is an option to 5w-20 mineral oil, (or 5w-30), will continue to require 5,000-mile/6-month oil change intervals, even if 0w-20 oil is used. In the case of vehicles with 10,000 mile oil change intervals, the 5,000 mile service interval has not been eliminated.