Don't feel bad - "blocks" are not standardized in America, there are not too many cities on a true grid system... and even then, the distance can vary greatly! Where I live, a block could be as little as .25 miles, or up to 1 mile (.4km to 1.6km) - every city (and subdivisions within cities) can be different. I'd say at most, it's a 10 mile (16km) move.