Ford 2003 Mustang Workshop Manual page 1004

3. If necessary, retract the tensioner pad retracting mechanism.
1. Compress the tensioner pad retracting mechanism.
2. Insert a retaining pin.
4. Turn the camshaft sprocket so that the timing mark is on the bottom of the balance shaft (6250).
5. Install the timing chain, the camshaft sprocket and the crankshaft sprocket.
6. Make sure that the timing marks and the keyways are aligned.