The block is amazingly light and could weigh less than the crank.
With the pistons assembled, I cleaned the deck of the traces of head gasket where I could feel it when I dragged a fingernail over it. Interestingly bank 1-4 started out with significantly less old material around the water and oil passages than 5-8. I used 1200ish wet/dry sandpaper with wd40 to lubricate the decks. Lots of grime left on the surfaces which I'll clean off with a good spray down with cleaner.
1-4 after working it over:
and 5-8 during the process. I ended up using some Permatex gasket cleaner on this side which helped get the last bits off.
I also cleaned the mating surface for the coolant gallery cover and the rear main seal assembly on the back of the block with Permatex Gasket cleaner and a very gentle scraper to get the 20 year old paper gasket remains off.
The block has several of these very small hex head plugs scattered around the bottom. I assumed they are drain plugs (in addition to the two large plugs on either side) so I pulled several that came out easily (several, like below, didn’t budge so I left them in rather than strip the hex head). My plan is to reinstall them with a little blue loctite to ensure a good seal after I do a final cleaning of the block with brake cleaner, once I size all the rings.
****update***
I traced the fluid path leading to these small plugs and they are plugs in oil passages which lead to the oil squirters under the pistons. The oil flows under the valley in a tube cast into the block to the back where it hits a spring valve. I assume this keeps the oil in the head until it warms up, then the valve opens up and allows oil to flow down into the squirter circuits on each bank after which it simply falls into the pan below.