Jim,
My battery is not original nor a reproduction, it's a
Bosch S4 (see pic attached). There you can also see the clamp used. Some pics of how its mounted a correct concours battery will help.
Not sure of its size respect the two that were mounted on Mustangs.
No, I didn't know about the special tool
I'm not that domestic to get better shipping offers.! I'm in Spain, and once here, in Ibiza island, western Mediterranean.