Slant Six Coolant Drain

MeegsAp5 said
@dodgedart1968 thank you for asking this question, I spent quite a bit of time trying to find the plug yesterday. I have an overheating issue on a 1963 AP5 and I really want to ensure I get the cooling system as clean as possible.

If you look closely at the image I posted, you can see that it is located just behind the oil filter mount.