Continuing installing a replacement engine. I was going to try to start it on Wednesday, had gotten to the add water and coolant stage. The vacuum filler thing wouldn't draw any vacuum at all, so I added a quart or so of distilled water which leaked out below the new water pump as fast as I could put it in.
The gasket is leaking.
Darn it! There's this one bolt that is very difficult to remove. Gonna try again today. And then put it back in with copper RTV. I put the water pump in with those inside out torx and they are the fiddliest fasteners in tight places!