Stop in for a cup of coffee

Did you pull the piece out of the block?
Its basically 5/16 tubing with a bubble. Maybe 3/8”.

If hole is undersize, why not just drill it larger?

First - do what TJ suggested - check for whats in the hole.
Then do some measuring. :poke:
Your drill bit set can be used for pin gages - unless you have them new fangled ones..

Before you get too far down the path , one of the things to check is the dipstick length and tube combo puts the mark at the 4 qt level in the sump.
Never assume!

Waaaay too much logic being applied here...

:rofl: