my 440 A body 4spd is a 23 spline input with the large bearing retainer(not the od retainer) It is the large 727 output shaft. As far as I have seen only Hemis came with the 18 spine input shaft. That 18 spine is worth a lot. I would salt it away and buy the proper one, unless there is no chance you will ever do a b/e. All of the aluminum bell housings I have seen have the dual pattern, I haven't seen a steel bell housing for a long time.
