I am going to replace my timing belt on my 90

I use a paint marker to mark the belt and gears. then when I have the belt off I transfer the marks to the new belt. That way there is no mistake and getting it off one tooth. And you dont have to worry about trying to line up marks on the cases and head. Just make sure you know which mark is the one for the cam and which direction the belt is facing.(put an arrow for the direction of rotation).
Also replace the waterpump and the tensioner pully while you are in there.(saves you from doing it again if one of those go out)
Hope this helps
(:DK

Try this: