Carpokes

Hi all, I'm looking for the exact freeze plug size inside the block of a 3.0L engine. Not the ones at the ends of the block but the internal one next to cylinder 1. It blocks off coolant between the bottom of the motor and the oil cooler internals. It's only visible with the oil pan off the block. It measures at 16mm but I want to verify the size.
Does anyone have a source for this little gem?

I have a 104mm block from a 2.7 '89 motor on a stand without the pan. Will check it today...

Thanks Tom, I'm pretty sure it's 16mm. My next question is installation. Use anaerobic flange sealant? Permatex Ultra Grey? Freeze it first?

This block was prepped by Jason Lee (Heritage Motorcars, for those who remember him). I forgot that he tapped all the freeze plug holes for threaded plugs. 16mm looks about right for the original hole, but I can't know for sure since it's tapped out for NPT threads. For what it's worth, Jason's instructions at the time was to use original JB Weld on the threads to seal it. Sounds a bit hillbilly, but he built some impressive engines back in the day, and was recommended to me by Jon Milledge, so not just idle facebook advice...

@michaelmount123 might have some good insights too....

I found a 16.2mm freeze plug locally, sounds right to me. I like the JB weld idea. I'll see if Michael knows the real deal, this motor will have one of his heads on it.

Thanks Tom