Found a useful thread on F-150 forum
“Remember that the crank doesn't care if you are on the compression or exhaust stroke... only the cam cares. So long as you align one dark link on each chain with the mark on the crank gear and the other dark link with the L or R (depending on the respective side of the engine) on the phaser, you will be in time. Note that on this engine, when you complete enough revolutions for the dark links to align with the crank gear mark again, they will not line up with the phasers. IIRC, it was some 38 revolutions of the engine before the dark links line back up with both the crank and the phasers at the same time. As long as you start with crank and phaser marks aligned with the dark links, you will be ok.”