'68 318 - Coolant left in heads when removed.

Darter6 said

View attachment 1715780513
This is a 68 engine. At the right of the motor mount bolt you will see a boss in the block with the mentioned pipe plug. It is not un-common that even after removing, the rust deposits will have formed and nothing will come out.A cost hanger jabbed in will loosen debris.Now may be the time to think about pulling and replacing the freeze plugs.You will be amazed of the crap that you can dig out of a 50+year old block.

Click to expand...

Thanks! That's really helpful.
The engine is still in the car right now, and from what I'm reading I may save messing with the plug at a later date, when I am ready for an engine pull and tear down. I am sure there is a lot of junk in my block, though.

If I could ask for another favor, could you show where the timing marks are in a '68? As I understand it they moved on 69 and later small blocks, being on the right side of the timing chain cover, but I've not been able to find them on my 68.