All cylinders filling with water

Still doesn't explain how all 8 got filled.

I have some Stock J heads $150/pr. Need a complete going through and 1 exhaust valve at a minimum.

You have a bore scope you can run down the intakes to look if it's coming from the port(s)? Maybe a HF quick rental... :)

Take a scribe and see if you can move any of the top row head stud washers.