My block is an '83, 300 thousand + miles of burned in junk inside and out, one hour of using this stuff. I did the engine cleaner first, it was from NAPA, did very little, was a disappointment on how weak this stuff is now. So I tried this from Dawn Professional Products I found on Amazon, amazing.
I did 2 coats, half hour each, on a dry surface and kept it wet with more and a soft brush moving it around and forced air dry between coats.
I have NEVER cleaned a block this bad without echoing the surface this fast, it did not foam up like Sodium Hydroxide does and turn the surface dark and etch the bearing surfaces.
I will still have to clean off the Loctite 574 but that is a small price to pay to not spend DAYS cleaning engine parts.
Old Fart out, flame on Gents..