So I was playing in the shed today as you do when it is the Brisbane show day public holiday.
I was comparing a head gasket to the face of a 12G940 head when I noticed the head was rattling. Something was in the water gallery. Turns out there are some core support bars that are meant to melt during the casting but didn't and have been in the water jacket for ever. I dug them out, see the pics:
Here's what I could see through the heater tap hole after I had already broken off some little bits:
Here is the whole lot sort of re-assembled. The thin bits were attached to the other parts.
There are some other dags visible in the thermostat well where the halves of the sand cores meet. I snapped a few off with a screw driver.
When people complain that their car overheats, maybe they have a poor casting? This one just rattled and didn't seem blocked but if it didn't rattle I wouldn't have gone fishing in there with a coat hanger.
M
No 6S quality systems in the 60's ? 
