Block cleanliness

if it has been sitting long enough to get that much junk in it again, it may be best to have it tanked again and new cam bearings and soft plugs installed, I do not think that will hurt the bores, or, as was suggested previously, wait till you get it all put together then flush it out real good.
I would remove the soft plugs to get it cleaned out better... they are CHEAP compared to plugging up your radiator and heater core and possibly overheating your new engine!