Cylinder 8 not firing

Did anyone mention that there has to be a combustible mixture in the chamber? I mean is/are the valves opening? A compression test, and a cylinder leakage test will only prove that they are closing.
I see in post #1, that Trevor says the rockers are going up and down, but are they going up all the way? and is the piston pulling a charge.
If an intake lobe is going away, or it's pulling air from the valley, well .... You get it.

But also from post #1, since the heads and cam are being replaced, and the compression numbers are pretty good, why are we even ..........................