I'm considering using some older Dura Ace 7402 cranks. I thought I had the chainline figured out for my particular build, but then realized when i rechecked the Sheldon Brown archive (http://sheldonbrown.com/bbsize.html#shimano) that the original bottom bracket for these cranks was asymmetric. The original BB was 112mm, but had 3mm extra on the right side.
So, as I'm figuring out the chainline using a new symmetric BB, does the extra 3mm mean that I should compensate in my measurements by pretending that the original BB was 115mm? Seems like that would be the logical thing to do, but I'm not quite sure.
Thanks for any clarification.