Ford 2003 Mustang Workshop Manual page 1353

33. NOTE: The crankshaft pulley must be installed within four minutes of applying the sealant.
Apply silicone gasket and sealant to the Woodruff key slot on the crankshaft pulley.
34. Using the special tool, install the crankshaft pulley.
35. NOTE: Use special tool 303-009 or a suitable strap wrench to hold the crankshaft pulley.
Install the washer and the bolt. Tighten the bolt in four stages.
Stage 1: Tighten to 90 Nm (66 lb-ft).
Stage 2: Loosen one full turn.
Stage 3: Tighten to 50 Nm (37 lb-ft).
Stage 4: Tighten an additional 90 degrees.