[bobH]

I'd offer the opinion that the picts shown by the professor do NOT represent what has happened in five months. Probably been a good long time since those parts were really clean. Seems like it was posted some time ago that his engine was hot-tanked (or some modern substitute) at rebuild time. No way the current 'tank-cleaning-methods' are going to get this sort of stuff out. My guess would be that these pumps are quite a bit older than 5 months, perhaps even the 30K miles that has been mentioned. There have been several old posts on what it takes to really clean a block, and I would defer to those posts.
Seems like Ron, and maybe JWL, have mentioned the 'bake n shake' method of block cleaning. And, there have been a few posts on the chemical cleaning process (which some of us are a little afraid of). And, there have been posts on here regarding the technique of poking down through the deck holes to break-out the bad stuff, with a sharpened slim steel rod. And, even one post about running a long drill from the front, through the water-pump hole, to drill through some nasty rust between the cylinder and the wall. As far as I'm able to recall, I don't think Henry reported on any of this stuff being done at rebuild time. I'd speculate that his engine had a 'cursory' cleaning, with most of the old stuff remaining in there. Just speculation, JMO.