Mopar street car, full body car, leaf spring or maybe ladder bar car. Stock eliminator - Dana is fine.

Everything else - 9".

The steel banjo housing can be braced and made much stronger than the cast or forged center with tubes pressed into it. And it makes fabrication easier.

Anyone who's ever tried to find someplace to attach 4 link brackets on 18" centers, non-parallel wheelie bar mounts, anti-roll brackets, shock mounts, locator brackets, etc, etc on a housing in a small body, big tire car gets it.