Let's see ... '55 Drysdale ... would the appropriate brakes have been Universal Extras? GB Coureurs? Even (gasp!) Weinmann sidepulls? The last-named would be period correct, and would have the virtue of being reasonably easy to find, I should think. I've seen a set of Universal Extras for sale (at least one set at the Cirque, but I misremember who had them), and there are bound to be some GBs somewhere.