If its an 0811 it should have the Ford 110 engine. According to the Ford Cargo Workshop Manual, the re-fill capacity is 14 litres if it has a front well or 14.6 Litres if it has a rear well. If the oil cooler (if you have one) was drained as well (there is a drain plug on the underside of it) - add another 0.7 Litres.
Good idea to put some clean oil into the filter before screwing it on - helps to build up oil pressure sooner when you re-start.
Make sure truck is on level ground when checking dipstick!
Overfilling the engine with oil can be almost as bad as underfilling it.
JD, October 2008
Except he is talking about a Ford Cargo you thicko.
Will probably need between 4 and 5 gallons.
Thats what you get when the "think I know about car mechanics" cross over to the big stuff.
Bob, October 2008
Most motors hold less than a gallon,drain it, fit a new filter,warm engine up for 5 mins let it settle then top it up a bit at a time and read the dipstick!Easy.