The adapter that gbody sells...
The adapter can break around the oring grooves due to the thickness of the material in that area. Also people buy spares to drill a hole or holes for alky injection. That adapter he is selling is the exact same one as the one on your car, but I think there is an option to have the inside machined smooth.
So those are normally the two reasons people buy the adapters.
I have also seen the adapter heliarc welded to the end of an 86/87 turbo housing.
Either way you go keep everything clean and have fun.
Jerry jr.