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A good quality putty knife with a stiff blade that is razor sharp will get the bulk of the crud on the flat surfaces on the head, block and manifold cleaned off. I sharpen my putty knifes on a fine grade wheel on my bench grinder.

Follow that up with a 4" fine grade wire wheel that chucks up in an electric drill. Use a drill that runs on 120 a.c. because most of the battery powered drills don't spin fast enough to make a wire wheel work efficiently. I'm a fan of the Forney brand wire wheels as they seem to last longer and have more bristles.

Most hardware stores have a bulk packages of around 10 small brushes similar in size to toothbrushes. Usually they have a mix of steel, brass and nylon in them. Very handy for getting into nooks and crannies.

For cleaning out bolt holes etc... get a couple sizes of the tube style wire brushes that chuck up in a drill. Once again Forney makes good ones.

I chase all of the threads in the blocks that I work on with taps then blow them out with compressed air.

As far as cleaning grease and grime aerosol brake cleaner is one heck of a solvent that doesn't leave much if any residue. Engine degreaser in an aerosol can leaves a residue that I don't like.
Simple green undiluted is another go to of mine along with acetone for a final cleaning of gasket surfaces and before painting.