Started this Easter Sunday with a little cleaning on 1/2 of the Corvair engine block. I found that WD-40 was a great solvent to cut through all of the accumulated muck. Used wire brushes, old toothbrush, screw driver and small Dremel brush as cleaning tools. Zep Citrus Degreaser removed the sludge created by the WD-40. When looking for an industrial degreaser at Home Depot I read all the labels and found that Zep Fast 505 was about the only one that did NOT exlcude cleaning aluminum. This cleaner did a nice job removing the varnish on the inside and final touch-ups on the outside. Will use a wire wheel to clean the studs.
This work was a bit tedious but did not take any extraordinary effort, special tools or expensive processes to achieve excellent results. I included the dirty block half in the photos to provide some before-after contrast.