Since you claim to be an expert in this subject.....
• How, EXACTLY, is a transmission aligned to a bellhousing?
And if the front bearing retainer is not 'designed' for this purpose, then why does MaMopar go to the trouble of dedicating a page in the service manual (section 6-9) to explain why the bell must be aligned to the block?
Perhaps no alignment is needed on any of these parts.......
As an edit, I have been challenged to post photos of my adapter for the A-833 to L6 bell. Since I do not (yet) make one I have no pics to offer. Until the previous photos had been posted I fully assumed that any adapter would, in fact, have some means of registration. For those that question the need I can only say to do a little research regarding parallel shaft mis-alignment and the resulting issues.