I just called the guy I bought it from. He said all the
oil galleys had those restrictors in them. I asked about how bad the problem was when he had it, he said that in 6 non-consecutive miles the coolant was gummed up and it was overheating. I’ve gone about 400 miles now and only added
oil, and I haven’t done anything with the coolant. That reassures me it’s likely a head gasket problem then, or it could be a crack in one of the head bolt holes still and the thread sealer I used helped slow the leak down. At least now I’m pretty sure that I won’t be needing to remove and replace the
oil restrictors, I can’t imagine how anything I did during reassembly would have slowed down a leak coming from there.