• If you're asking if the current JIS taper is different to your cranks' taper, then I don't know.

    There is "low profile JIS" (as used by 7400) and Shimano cranks were compatible with Campag cranks around the Super Record era, but I don't know who adapted to who's standard (or if there was a third one).

    Your cranks may be ISO anyway...

    Myself, I'd offer-up the cranks to whatever BB I happened to have available and see what that tells me. If you don't have any Engineer's Blue, use a marker pen to coat the taper of the BB and insert carefully (so as to not scrape down a side of the cranks); remove equally carefully and see what that tells you about the engagement.

    If it looks good, then install fully, measure the chainline and work from there.

  • It all gets a bit vague with Eighties parts and £30 is a lot to pay in a trial-and-error scenario.

    Shimano UN55 is available ITA 115mm and £15-odd: for the sake of 1.5mm on each side, I'd be tempted to give that a whirl.

    Or just get another set of cranks...

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