I'm not looking to get into a shooting war over this, and I agree with the coolant flow, but I don't agree it is OK to have mud filling the other passages. The coolant needs to circulate throughout the system, not just between the block and the head. All that mud comes from the internals of the coolant system components like freeze plugs, impellors, the block, radiator, and heater core.

I posted a photo of the head gasket to prevent this. Look at your head gasket. There are no other passages. Those ports, that you refer to, are sealed by the gasket. That's why deposits fill into those ports. It's not mud. lol. It's Iron.

Thank you. We will remember that....What a visionary....

I must try to be more thorough before I comment. Upon closer inspection I see now that the head gasket is still in place on that block. Randy Bobani was in no way suggesting clogged waterways is OK. He is correct, coolant needs to flow from the front of the block to the rear, and then up into the back of the head and back toward the front. If those casting holes were open through the head gasket coolant would not efficiently carry heat to the radiator. I will say however, if I’m going to be called a derogatory name for a technically accurate, but unnecessary comment, I prefer “Captain Obvious”.