Did you see the Y-pipe flanges since you posted about what your friend planned to do?
Have your friend machine both of those faces down until all of the pits are gone. What we see in your 25-Nov post isn't good enough for a proper long-term O-ring seal unless you're real lucky.
See this thread about that, including notes about maintaining flange flatness/planarity when milling it among other things.
While you're thinking about it what do the mating O-ring grooves look like on the block? Better than the Y-pipe flanges look? I didn't check your thread to see if there are teardown photos of the valley.