Ford 2003 Mustang Workshop Manual page 1535

5. Remove the timing chain (6268) and the camshaft sprocket (6256).
6. NOTE: LH tensioner is shown, RH tensioner is similar.
Remove the tensioner.
7. Remove the roller followers on the base circle.
1. Install the special tool on the valve spring.
2. Compress the tool and remove the roller follower.
8. Repeat the previous step for the remaining roller followers.
9. Remove the hydraulic lash adjusters.