The original clutch is a 10.5 inch disc with a diaphram clutch cover. It was refered to at one time as a Borg&Beck.
The original flywheel part number is a C5ZZ number, I don't remember the suffix.
You can use an 11 inch clutch but you will need to redrill the flywheel.
You can also use a Long unit if you can figure out how to get more travel out of the slave cylinder.
The Pantera clutch was always in the Ford parts book as a Pantera part, not a Mustang unit.
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