I'd pull that head off. The only other damage would be to the piston, readily visible then. Seems like a lot of extra work and money to pull it out if not needed
I would think the pan would be pretty easy to drop on that. Find out the oiling pattern and check the bearing furthest downstream. If it good the others should be too.
RA shows them being the same size as the SBC. They also show a .003 oversize probably for this situation. If you pulled out the old ones heated the head and cooled the stud you might get them in
I would check and see if they're the same studs as a sbc. If so you could get screw in studs for it. It would be better to do the threading with the head off but probably could be done with the head on if you're really careful. I wouldn't try replacing with press in, those holes are probably...
Also had to make this part. The flat disc was part of the original part. I sand blasted it then chucked it up in the lathe and cleaned up what was left of the original metal tube. Then used part of a p trap for the tube. Then cut an abs ring and glued it on.