Both dirk and Jon ,I know this isn’t the exact solution but I too have a pair of these and a lot of [cheap] modern brake shoes have a little extend piece of the shoes where the bolt threads in ,obv intend to countersink in modern brake arm slots but also slotted perfectly into the ‘cam’ disc on the original as in the photo ,cheers Stef,p.s there was an American site I think called Yellow jersey that sometimes showed the blocks for sale but it seemed a defunct or non- updated page
Both dirk and Jon ,I know this isn’t the exact solution but I too have a pair of these and a lot of [cheap] modern brake shoes have a little extend piece of the shoes where the bolt threads in ,obv intend to countersink in modern brake arm slots but also slotted perfectly into the ‘cam’ disc on the original as in the photo ,cheers Stef,p.s there was an American site I think called Yellow jersey that sometimes showed the blocks for sale but it seemed a defunct or non- updated page