Do I measure the width of the bottom bracket shell across the frame rather than the outside dimensions of the bottom bracket unit ?
If so, it measures 68mm spot on. I was especially surprised that the rockhopper would be 73mm because the '3a' code was mentioned which, according to sheldon brown, relates to 68mm bottom bracket shells.
I have a feeling Specialized started putting 73mm BB shells on Rockhoppers and Stumpjumpers at the same time they oversized the top tubes to 31.8mm. I think that was around 1990 or 1991, but don't quote me. The 3A code means nothing to me. Do you have a link to what Sheldon has to say about it?
That is really bad news if headset is jis as I've got a tange levin in the post which is iso and I've no idea where to get a jis one.
There are plenty around. The problem is that a lot of the time people don't know they've got them until they try to fit them to an ISO frame. Still, I could well be wrong about yours. The only way to be sure is to measure your frame and fork, or the headset you're removing.
Calmes dans le demi-jour
Que les branches hautes font,
Pénétrons bien notre amour
De ce silence profond.