Nick's photo shows clearly what you're looking for. Take a plug out of 1 or 4 to feel the piston is near tdc (taking all 4 out will make turning the engine easier).
Then look for the bolt head through the timing cover, you can turn the engine slightly to see the drive strap and be sure you got the right end of it. You can use metal polish or similar to help the marks stand out, it is possible there aren't any if the flywheel's been machined or replaced with one off a later car.
or the it has a verto flywheel assy.