I have been reading that the cam/ crank timing should be set "straight up". I understand this from a timing set standpoint. The stock timing is 4degrees retarded and any aftermarket timing set will either be set for straight up timing or have keyway settings for 0degrees, 4 advance or 4 retarded. In researching cam specs, the CompCams 255deh spec states that the intake centerline should be 106degrees, while all others have a centerline of 110degrees. Is "straight up" relative to the centerline of 110 or 106? If centerline is relative to 110, then 106 would be 4degrees advanded, not straight up. Please help with my confusion.
Keep in mind, I am trying to visuallize all this in my head before I actually purchase any of the parts. It has been 21 years since I last pulled an engine apart. When installing the cam, there is a dot on the cam gear which is supposed to line up a dot on the crank gear. What is the position of the crank, in degrees, when this happens, TDC of the intake stroke?
That reminds me of another question. How do I know that the crank and the cam are on the same stroke? the crank will revolve twice for each rotation of the cam and it could be on the intake or power stroke.

 

The comp cam website has some good explanations.

-Doesn't matter, the cam sets the valve operation.