Dura Ace 7400 Crank, ISO/JIS?

I have seen this discussed on several forums, but no definite conclusion.
Many would say that it is a JIS taper, some ISO, some say it lies in between the two standards.
I was just wondering as I have a nice 7400 Groupset on the way for my Gazelle and I'm hoping they will fit my Shimano BB-6400 (JIS), which currently holds my Exage 500EX cranks.
Any Idears? Thanks in advance

what the road ones?
jis

Think it's only the track ones that there's dubiety over.

Even then, just try and go with whatever they have been used with so far.

Aren't the ones that are JIS stamped thusly?

113mm jis

7400 BB was 110mm and there does seem to be some uncertainty as to JISness. All subsequent Dura Ace road square tapers were definitely JIS and JIS seems to be the closest fit for the 7400 cranks. Hard to find in 110mm though.

Untill recently I'd assumed all Japanese would have obviously been JIS. But I read (maybe on here) that this wasn't the case, apparently anything with NJS cert is ISO.
So assuming DA 7400 isn't NJS it would have to be JIS.
Just repeating what I've read, no personal experience.

I used a 110 jis bb on my 7400 as MrBump said.

Untill recently I'd assumed all Japanese would have obviously been JIS. But I read (maybe on here) that this wasn't the case, apparently anything with NJS cert is ISO.
So assuming DA 7400 isn't NJS it would have to be JIS.
Just repeating what I've read, no personal experience.

not just NJS, alot of Sugino and Suntour cranks are ISO up untill late 80's. they were cheaper alternatives to Campagnolo Record and were interchangable,
some of the earlier Shimano track cranks used a 107mm axle, not sure if it was JIS.

Maybe a really stupid question but can any BB shell fit either JIS or ISO BB without issue? I've just bought a new frame and not sure which crank set to go for...

threading is something of no relevance to taper type.
depends on that threading of the bb is

7400's are ISO

yup, sorry James. I meant to say track ones. :)

*edit, if he's getting the group set, it'll have gears, so JIS it'll be then

Thanks very much for the advice, it does seem to be JIS from trying it out on my 6400 BB. However, the left hand crank is not fitting into the spindle too snugly, there is about a 3mm gap.