I have limited experience with engines - I have only rebuilt (and/or changed head gaskets) on 5 216/235/261 engines.
Wait to hear from others for opinions on the status of your block.
The reason I asked for photos of the head gasket is to see if you have a 261 head gasket.
Some engine-rebuild gasket-kits come with two head gaskets: one for a 235 and one for a 261.
