Could this cause 0 compression

[gearheads78]

I am working on a fresh motor in a car I picked up with excellent compression on 7 clys and none on the 8th. The only thing I can find wrong is the cam is completely flat and lifters are ground down 1/4" basicly I don't think the valves were opening at all in that cly. My thought is as the piston goes down it creates a vacuum and when the piston goes up it fills the vacuum but never creates any positive pressure never moving the guage. Am I on the right track or am I way off base missing something else. Cly, head, gasket, valves, piston, and rings all look good.