Towing a 2640lb 16ft TT with a Ford Ranger 4.0L?

don't expect good mileage with the 4.0. I would go with a modern half ton if you are worried about mileage. any will handle that trailer even with the smaller motors. watch payload if you are living in it especially with older smaller tow vehicles. my 2002 jeep WJ would have been a good match for that trailer also though not the most efficient vehicle.