I'm an uninformed heretic. I use lacquer thinner and scotchbrite. Gets it clean, clean, clean.

Clean the head a bit and have it "surfaced" so it's perfectly flat and fresh.

 

Just decided to have the heads rebuilt locally. Eliminates one variable and might as well while do it now while it's apart.

As far as the block goes, this is as good as its going to get I feel. The marks remaining seem to be the start of pitting. I used a little spray paint and it revealed they were neither high spots nor low spots.

Looks like it should be assembly time soon!!

 

you should be in good shape with the heads being done . im sure it will be fine.... the block looked good, but just needed a little more scrubbing. much better to do that , than to take the chance of damaging something removing the studs and having issues with new studs or using the old studs after that assault on them to plane the top of the block
you should be fine.