18 spline abody box?

No they were not available. Yes it is possible to build one; my best friend did and ran it for a very long time w/ a dual disk clutch setup. I also had one a long time ago w/ Liberty gears and setup as a crashbox, but I sold it before I ever found a use for it.

I'm deployed right now, but I'll see if I can get ahold of him to chime in on this.