Originally Posted by Doug Fattic

There are several things you can do to help make a 40/50 Campy brake to work wth your fork. Many brakes come with a kind of spacer that holds out the brake a little further from the fork crown. I'm not talking about the star washer although a couple of them might work too. It is thicker. This is usually to get the brake away from hitting the lower headset. If the brake goes out a bit, the blocks have to be set a bit higher in the slot because the rim is rising up. It works in reverse in the rear. You can also safely file use a title on the brakes slots to length them a little. The best way to do this is to remove the brake blocks of course and then use a round file the same diameter as the slot and place it across both slots to help keep it oriented. Of course there are many 47/57 brakes both vintage and modern dual pivots (that brake even better) that will work.