I don't know why Gary hasn't chimed in by this point. Though there may be some optical reasons for seeing it otherwise, it must, indeed, be a nut because Gary asks if he should remove the off-side nut. The stud is not broken. Gary misinterpreted what was going on on the LHS. If the stud were, in fact, broken, Trevor's advice would be what I went with, that is, leave it. If the bottom has not been opened since '72 after sitting a long time, then working on the top end, there is a fair chance it will need to be opened soon when sludge blocks the journal oil holes. Sounds pessimistic doesn't it.
Richard L.