I bought a 2005 cavalier that had jump time and damaged the valves, I am replacing the head my question is how do I know with #1 cylinder up if it is correct in regards to ignition timing or could it be 360 degrees off?????

 

If you are doing this by yourself, I use a kleenex in the spark plug hole. Slow crank it till the kleenex pops out the spark plug hole on number 1 cylynder

 

Both valves should be closed.