This might be a slightly silly question, but here goes:

I've acquired a 1947 light roadster, probably an Elswick:



The sloping top tube has got me wanting to make it into a path racer replica of sorts, probably a single speed. In that case, I'm going to flip the bar over and therefore want to install calliper brake. Obviously the frame is drilled for rod brakes, so is there any way I could install cabled brakes instead? Will I have to drill the frame again? Thanks!