Technical Cadillac 365 mystery hole

Purchased a 365 Cadillac long block and piecing it back together. Noticed this hole next to water pump. Is that oil sender or what.

 

We could tell you, but we’d have to kill you.
Would that be for a heater hose?

 

Is it the one next to the “A”? It looks like something is in it. If it’s threaded a bracket of some kind for a brace on something. If your not going to us it an Allen set screw will protect it.

 

1/8" pipe thread. Oil filter return line fitting lives there.
If no filter, just plug.

 

Makes sense. I remember the filter being high up on the front of the engine.

 

Heater lines. Oil filter canister tube line connections are at the front of the valley and on one of the heads.

 

Not heater, guys. I think he's talking about this one...

In the mean time, maybe this will help some. Amazing what is already here.
https://www.jalopyjournal.com/forum/threads/cadillac-331-oil-lines.1143026/

 

Can't say as I have ever had a "mystery hole".

 

Seems like post 7 from the quoted thread & post 5 from this thread were written by the same guy.

 

You are off to a great start, clean up the grooves in that pulley. It will "sand" your belts down!

 

42merc, that guy must have a feel for them engines!
Hope the more involved pictures and descriptions help OP, and thanks for all you do!

 

Oil line For the Win...