You had it dyno'd ? Maybe the dyno room techs might have told their buddies about "this killer small block we ran in the cell...."
Thins is.... For someone to come get it and come prepare to lift it and take it, you can be sorta certain it was not random.
Your buddies who told their friends, the guys at the parts n pieces store where you got the cam & heads and stuff
Tracking it down without sparking a war with a bunch of innocent folks will be hard, but its not likely that it was taken by someone from 3 time zones away in a random act