I believe that the cam gears are oiled from the main oil gallery that runs through the "valley" in the center of the engine. In the front of the galley, there is the oil pressure relief valve consisting of a spherical piece held on its seat by a spring. The spherical portion has two "flats" on the sides which allow a certain amount of oil to leak past. The oil that leaks past is what lubricates the cam gears. There is also a certain amount of oil which is churned up in the oil pan and sprayed off the crank. This is what occurrs as I understand it. If I'm wrong, I presume someone will point out the errors in my thinking. Good Luck with your truck.
