It's tough to say what enough break in is. An optimally broken in engine has maximum compression with no metal "pinch" at the top of the piston stroke (you can tell by turning the engine with the plug out). This usually doesn't take place until after the engine has been driven on he track a little bit. You are probably ok sending the engine to a modder like it is now though.
What engine? I ask because I'm not a big believer in modding. If it's a good engine it's probably better to leave it alone.