Looks like a Oil sender Hole ? Driver's side front just about covered with intake manifold on. Is that under Oil pressure ?

I need to deal with this before I install the Intake manifold is a 1989 2.9 ranger 4x4 auto transmission

I hate to not know what this threaded hole is for?
Hello Forum :)
I got this 1989 Ranger as a project with the cracked Heads off . However I did here it run before they where removed before I got it .
I just happened to have a perfect set of Good Heads and installed them today . However I noticed a Threaded Hole in the Block on the Drivers side just in front of the Cylinder head . It looks like a oil Sender hole . When I go to Install the lower intake manifold it almost covers it up but you could see it if you look close .

I think I need to know what this Hole is before I continue installing the Manifolds and such . Perhaps I should plug it up ?
Thank You in advance if anyone knows for sure exactly what this threaded hole is for . I need to know what to do about it

Thanks in advance for any Help as I need the truck and want to finish it up ASAP
PS the Truck I heard run and in fact I drove it, problem was a Lot of steam out the Exhaust but it still ran quite . The head's where badly Cracked but the Block looked fine in fact as well as the Cylinders .