i recently puchased on old frame for a single speed conversion. i bought a 700c wheel with a bmx freewheel on it and some shimano600 brakes. i went to put the brakes on the rear and they wont fit and even if they did the reach was not long enough. am i doing something wrong? maybe a dumb question but i would appreciate some help. thanks!!
I measured the reach on my 27" single speed (which previously had fenders) and they're about 65-75mm. You can source long reach brakes on ebay sometimes, or a website called YellowJersey.
Hope that helps.
Tektro makes pretty descent long reach (47-57mm), and extra long reach (55-73mm) calipers. You can get them for pretty cheap (just change out the pads if you get the lower end ones, the stock pads are crap).
As for the hole, it's for old style nutted brakes. You can used newer recessed brakes but you have to drill the hole out with a 5/16th bit. Use cutting fluid too, and be super patient or you can end up screwing up your drill.