All cylinders filling with water

MiradaMegaCab said
Is the water ports/thermostat housing isolated or connected to the intake runners/plenum on the M1 intake manifold?
When pressure testing the cooling system, leave the carb off to see if any water is getting in that way.

No it is not. There is only 1 water log and it is at the front of the intake at the thermostat.

See the picture in post #120