Need 4-speed Help

There have been different A 833 transmission input bearing sizes according to engine and year( ie. HEMI/440, std, & O.D.)... Is the input bearing diameter can be 5.125", 4.80", or 4.35"... Does this need to match the opening of the new housing to be aligned... I believe it does if you are using an original factory bell housing... This could be a possible alignment issue if there is any slop in the bolt up (example the original bell housings sometimes have as many as 12 holes on the tranny side, but the castings are machined relatively square or I should say parallel to the bell housing/engine, so that the tranny is aligned).... Maybe I'm just rambling, not to be confused with a Rambler (AMC)... Good luck on the next tests....