Guys, the standard Campagnolo Nuovo Record bottom bracket is 112 mm with a +3mm drive-side offset (this is for pre-1977 bottom brackets).
http://www.campyonly.com/
When there is a +3mm drive-side offset, you must add +3mm to get a symmetric bottom bracket size, which would be 115mm (symmetric.) I am using a 115mm UN-71 with my SR Royal campy-copy cranks and they seem to be happy, although the ISO taper seems like it might be able to draw down a little bit further onto the JIS spindle. Still, I have never seen a failed BB that suggests a JIS/ISO mismatch causes crankset failure.
So : 112mm with +3mm drive-side offset 115mm with symmetric spindle 116mm or 114mm symmetric won't kill your chainline.
So 112mm = 75mm + 20/17 = 112 mm.
For a 1977 and later bottom bracket, it was widened to 114.5mm. The designation was 68-ss-120 + 1 + 1.5. I'm assuming this means +1 added to the non-drive side, and +1.5 added to the drive side, which is a 3.5mm asymmetric bottom bracket (114.5mm asymmetric = 118 symmetric).
http://www.campyonly.com/
You DONT want a +5mm asymmetric bottom bracket, those are for modern triples I believe.
- Don Gillies
San Diego, CA, USA