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.
Ford, Volkswagen and Porsche, for example, recommend oil changes every 10,000 miles. So does Toyota on several engines, including the Prius' 1.8-liter four-cylinder and the Camry's 2.5-liter four-cylinder. BMW says owners can go up to 15,000 miles between oil changes (with synthetic oil). The intervals vary by manufacturer and engines, so consult your owner's manual or maintenance schedule to see how often to change the oil in your vehicle and what type of oil to use. You may be surprised.