Thanks, Fastmark! I don't know how mine got switched to the larger shaft. I thought (usually wrong tho!) I had purchased a 1970 box from Year One (3 years ago) and also a sector shaft for a 1970. I know it was expensive! They are the large diameter tho. I thought for sure I bought the 1970, non AAR item. Now, I get to buy another for the smaller diameter sector. Oh well! Thanks! Jeff