You should take some finger nail polish and mark the block, where the distributor sits, before you remove it. That way when when you put in back in you can find the marks you put on the block to put it back exactly where it was. I prefer using white paint, easy to see, use the small brush and paint and mark the block in the front where the distrib and the block meet. Also where the point is on the Dicstributor points toward the hump on the valve cover is another good place to leave a mark.
This way you will not end up needing to retime the engine.
Also, get a paper pad and write down the placement of any vacuum hoses you remove off the vacuum advance.
