I would like to use the A-518 overdrive tranny in my B-body with my 440. I have read the articles on what to do and how its been done, but here is my question, Can the internal parts of a 518 be put inside a big block tranny case or is it totally different? I've heard the 518 described as a 727 with an overdrive added. Is there more to it? I'm not fond of using an adapter plate or cutting and swapping bellhousings from one to the other.