Before I put the heads on I did clean up the areas I could get to. I used a shop vac to keep as much debris from falling into the block as possible, I think your right a flush may be helpful considering. Here is a pic after it was cleaned. Before I put the manifold on Ill clean it again to get the spots i missed.

 

That engine is just too clean. I don't think that I would be able to put oil in it and use it.