Kalavinka will measure the distance from the fork crown to the rim. On my track fork it was too tight for a brake, so he sold me an old pair of Kalavinka forks for 3,000 yen.

Bring in the caliper you want to use - I think the ones that work with the tightest clearance is old Dia Compe Aeros. Shimano generally allow for tighter clearances than Campagnolo.