I'm re-assembling my 289. My question is, with the timing marks on the timing chain sprockets lined up, shouldn't the pointer be at 0 degrees? Mine seems to point at about 4 degrees.

 

Yes they should line up, however, there is a cetrain amount of "slop" in the valve system. you will find if you move the crank so that it reads 0, the dots on the timing gears will still look as though they line up. Just by looking at the dots, you cant tell if they are perfectly lined up. All they are there for is so that you dont get the gears out of line by a chain link.
Of course, you may have an aftermarket mutikeyway timing set on there. If so, there are multiple positions that the gears can be installed to ensure that when your engine is at TDC, you cam is a is"straight up".
It easy to tell if you do have a multi keyway set on there. there will be a few extra keyway slots cut into the gears around the center shaft hole.
I just thought of something. How can you tell the engine is at TDC from the timing mark. The timing cover has to be removed to see the dots on the cam gears????