Therefore:
* Cylinder #1: Front, passenger side.
* Cylinder #2: Rear, passenger side.
* Cylinder #3: Front, driver side.
* Cylinder #4: Rear, driver side.
* Cylinder #5: Front, passenger side.
* Cylinder #6: Rear, passenger side.
* Cylinder #7: Front, driver side.
* Cylinder #8: Rear, driver side.
This is true for both the 4.6L and 5.0L Coyote and 5.4L modular engines commonly found in Mustangs. Always double-check your specific engine's configuration if you're unsure, by consulting a repair manual specific to your year and model.